updated with pointers
This commit is contained in:
Jidong Xiao
committed by
JamesFlare1212
JamesFlare1212
parent
6670134276
commit
727b4fccd0
@@ -5,33 +5,25 @@
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<title>Morris Post‑Order Traversal Animation & Code Display</title>
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<style>
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html, body { margin: 0; padding: 0; font-family: Arial, sans-serif; }
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h1 { text-align: center; margin-top: 20px; }
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p { text-align: center; margin: 10px 0 30px; }
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.container {
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display: flex;
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justify-content: space-between;
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max-width: 1200px;
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margin: 0 auto;
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padding: 20px;
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}
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h1 { text-align: center; margin-top: 10px; margin-bottom: 5px; }
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p { text-align: center; margin: 5px 0 15px; }
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.visualization-container {
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display: flex;
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justify-content: space-between;
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max-width: 1200px;
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margin: 0 auto;
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height: 80vh;
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height: 88vh;
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}
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.code-container {
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background-color: #f0f0f0;
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border-radius: 10px;
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padding: 20px;
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padding: 15px;
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width: 48%;
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overflow-y: auto;
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height: 80vh;
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font-size: 16px;
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height: 88vh;
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font-size: 15px;
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}
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pre {
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@@ -54,16 +46,16 @@
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.tree-container {
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background-color: #f0f0f0;
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border-radius: 10px;
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padding: 20px;
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padding: 15px;
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width: 48%;
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height: 80vh;
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height: 88vh;
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position: relative;
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display: flex;
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flex-direction: column;
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}
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#nextStep {
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margin: 10px;
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margin: 10px auto;
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padding: 8px 15px;
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font-size: 16px;
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width: fit-content;
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@@ -72,31 +64,72 @@
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color: white;
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border: none;
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border-radius: 4px;
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display: block;
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}
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#nextStep:hover {
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background-color: #45a049;
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}
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#nextStep:hover { background-color: #45a049; }
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#nextStep:disabled { background-color: #cccccc; cursor: not-allowed; }
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#nextStep:disabled {
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background-color: #cccccc;
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cursor: not-allowed;
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}
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#container {
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flex-grow: 1;
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width: 100%;
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}
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#container { flex-grow: 1; width: 100%; }
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.explanation {
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margin-top: 15px;
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font-size: 16px;
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padding: 15px;
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margin-top: 10px;
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font-size: 14px;
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padding: 10px;
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background-color: #e8e8e8;
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border-radius: 5px;
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}
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.color-key {
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display: flex;
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flex-wrap: wrap;
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gap: 8px;
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margin-bottom: 5px;
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padding: 8px;
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background-color: #e8e8e8;
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border-radius: 5px;
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}
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.color-item {
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display: flex;
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align-items: center;
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margin-right: 10px;
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font-size: 13px;
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}
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.color-box {
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width: 16px;
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height: 16px;
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border-radius: 3px;
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margin-right: 4px;
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border: 1px solid #888;
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}
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.color-arrow {
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position: relative;
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width: 24px;
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height: 3px;
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margin-right: 4px;
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}
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.color-arrow:after {
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content: "";
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position: absolute;
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right: -2px;
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top: -4px;
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border-left: 6px solid;
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border-top: 4px solid transparent;
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border-bottom: 4px solid transparent;
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}
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.dotted-line {
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width: 24px;
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height: 0;
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border-top: 2px dashed #ff5722;
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margin-right: 4px;
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}
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</style>
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<!-- Load Konva.js from CDN -->
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<!-- Load Konva.js -->
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<script src="https://cdn.jsdelivr.net/npm/konva@8.3.13/konva.min.js"></script>
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</head>
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<body>
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@@ -126,7 +159,7 @@
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<span class="line-number">18.</span> current = current->right;
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<span class="line-number">19.</span> }
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<span class="line-number">20.</span> }
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<span class="line-number">21.</span> reverseTraverseRightEdge(root); <span style="color:green">// traverse the final right edge</span>
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<span class="line-number">21.</span> reverseTraverseRightEdge(root); <span style="color:green">// final right edge</span>
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<span class="line-number">22.</span> <span style="color:blue">return</span>;
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<span class="line-number">23.</span> }
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<span class="line-number">24.</span>
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@@ -149,11 +182,43 @@
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<span class="line-number">41.</span> std::cout << current->val << " ";
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<span class="line-number">42.</span> current = current->right;
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<span class="line-number">43.</span> }
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<span class="line-number">44.</span> reverse(tail); <span style="color:green">// restore the original tree structure</span>
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<span class="line-number">44.</span> reverse(tail); <span style="color:green">// restore structure</span>
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<span class="line-number">45.</span> }</code></pre>
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</div>
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<div class="tree-container">
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<div class="color-key">
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<div class="color-item">
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<div class="color-box" style="background-color: #ffeb3b;"></div>
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<span>Current Node</span>
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</div>
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<div class="color-item">
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<div class="color-box" style="background-color: #2196f3;"></div>
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<span>Rightmost Node</span>
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</div>
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<div class="color-item">
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<div class="color-box" style="background-color: #4caf50;"></div>
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<span>Visited Node</span>
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</div>
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<div class="color-item">
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<div class="color-box" style="background-color: #03a9f4;"></div>
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<span>Thread Created</span>
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</div>
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<div class="color-item">
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<div class="color-arrow" style="background-color: #888;"></div>
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<span>Tree Edge</span>
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</div>
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<div class="color-item">
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<div class="dotted-line"></div>
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<span>Thread Edge</span>
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</div>
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<div class="color-item">
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<div class="color-arrow" style="background-color: #e91e63;"></div>
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<span>Reversed Edge</span>
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</div>
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</div>
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<button id="nextStep">Next Step</button>
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<div id="container"></div>
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<div class="explanation" id="treeExplanation">
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Post-order traversal output: <span id="output"></span>
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@@ -182,8 +247,8 @@
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// Update the explanation text.
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function updateExplanation(text) {
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document.getElementById('treeExplanation').innerHTML =
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'Post-order traversal output: <span id="output">' +
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document.getElementById('treeExplanation').innerHTML =
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'Post-order traversal output: <span id="output">' +
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document.getElementById('output').innerText + '</span><br>' + text;
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}
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@@ -213,46 +278,93 @@
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fontFamily: 'Arial',
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fill: 'black'
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});
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this.leftEdge = null;
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this.rightEdge = null;
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this.threadEdge = null;
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this.reversedEdges = [];
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}
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}
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// Initialize Konva stage and layer.
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const stage = new Konva.Stage({
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container: 'container',
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width: document.querySelector('.tree-container').clientWidth - 40,
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height: document.querySelector('.tree-container').clientHeight - 140
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width: document.querySelector('.tree-container').clientWidth - 30,
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height: document.querySelector('.tree-container').clientHeight - 140
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});
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const layer = new Konva.Layer();
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stage.add(layer);
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// Draw an edge between two nodes.
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function drawEdge(parent, child, color = '#888') {
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const line = new Konva.Line({
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points: [parent.x, parent.y, child.x, child.y],
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stroke: color,
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strokeWidth: 2
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});
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layer.add(line);
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return line;
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// Calculate connection points for arrow drawing.
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function calculateConnectionPoints(fromNode, toNode) {
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const nodeRadius = 20;
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const dx = toNode.x - fromNode.x;
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const dy = toNode.y - fromNode.y;
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const angle = Math.atan2(dy, dx);
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return {
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fromX: fromNode.x + nodeRadius * Math.cos(angle),
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fromY: fromNode.y + nodeRadius * Math.sin(angle),
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toX: toNode.x - nodeRadius * Math.cos(angle),
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toY: toNode.y - nodeRadius * Math.sin(angle)
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};
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}
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// Highlight or unhighlight a node.
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function highlightNode(node, color = '#8bc34a') {
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if (node && node.shape) {
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node.shape.to({ fill: color, duration: 0.25 });
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// Create an arrow between two nodes.
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function createArrow(fromNode, toNode, color = '#888', dashed = false) {
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const points = calculateConnectionPoints(fromNode, toNode);
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const arrow = new Konva.Arrow({
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points: [points.fromX, points.fromY, points.toX, points.toY],
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pointerLength: 10,
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pointerWidth: 8,
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fill: color,
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stroke: color,
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strokeWidth: dashed ? 1 : 2,
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dashEnabled: dashed,
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dash: dashed ? [5, 5] : null
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});
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layer.add(arrow);
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return arrow;
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}
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// Draw an edge between two nodes.
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function drawEdge(parent, child, isLeft = true) {
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const arrow = createArrow(parent, child);
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layer.add(arrow);
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if (isLeft) { parent.leftEdge = arrow; }
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else { parent.rightEdge = arrow; }
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arrow.moveToBottom();
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return arrow;
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}
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// Create and remove thread edges.
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function createThreadEdge(fromNode, toNode) {
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if (fromNode.threadEdge) { fromNode.threadEdge.destroy(); }
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const threadArrow = createArrow(fromNode, toNode, '#ff5722', true);
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fromNode.threadEdge = threadArrow;
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threadArrow.moveToTop();
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layer.draw();
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return threadArrow;
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}
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function removeThreadEdge(node) {
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if (node && node.threadEdge) {
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node.threadEdge.destroy();
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node.threadEdge = null;
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layer.draw();
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}
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}
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// Highlight and unhighlight a node.
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function highlightNode(node, color = '#8bc34a') {
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if (node && node.shape) { node.shape.to({ fill: color, duration: 0.25 }); }
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}
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function unhighlightNode(node, color = 'white') {
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if (node && node.shape) {
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node.shape.to({ fill: color, duration: 0.25 });
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}
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if (node && node.shape) { node.shape.to({ fill: color, duration: 0.25 }); }
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}
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// Calculate tree layout.
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const stageWidth = stage.width();
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const stageHeight = stage.height();
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const centerX = stageWidth / 2;
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const topY = 50;
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const topY = 40;
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const levelHeight = stageHeight / 4;
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// Build the 9-node binary tree.
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@@ -281,15 +393,14 @@
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layer.add(n.label);
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});
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const edges = [];
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edges.push(drawEdge(node1, node2));
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edges.push(drawEdge(node1, node3));
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edges.push(drawEdge(node2, node4));
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edges.push(drawEdge(node2, node5));
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edges.push(drawEdge(node5, node6));
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edges.push(drawEdge(node5, node7));
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edges.push(drawEdge(node3, node8));
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edges.push(drawEdge(node8, node9));
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drawEdge(node1, node2, true);
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drawEdge(node1, node3, false);
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drawEdge(node2, node4, true);
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drawEdge(node2, node5, false);
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drawEdge(node5, node6, true);
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drawEdge(node5, node7, false);
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drawEdge(node3, node8, false);
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drawEdge(node8, node9, true);
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nodes.forEach(n => {
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n.shape.moveToTop();
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@@ -297,11 +408,81 @@
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});
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layer.draw();
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// Reverse a chain of right pointers.
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function reverseChain(head) {
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// Visualize the reversal process.
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async function visualizeReversal(head) {
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const connections = [];
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let current = head;
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while (current !== null && current.right !== null) {
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connections.push({ from: current, to: current.right });
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current = current.right;
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}
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for (const conn of connections) {
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if (conn.from.rightEdge) {
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conn.from.rightEdge.destroy();
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conn.from.rightEdge = null;
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}
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}
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let prev = null;
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let curr = head;
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let next;
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current = head;
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while (current !== null) {
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const next = current.right;
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if (prev !== null) {
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const reversedEdge = createArrow(current, prev, '#e91e63');
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current.reversedEdges.push(reversedEdge);
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reversedEdge.moveToTop();
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}
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prev = current;
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current = next;
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layer.draw();
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await waitForNext();
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}
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return prev;
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}
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// Restore the original tree structure.
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async function visualizeRestore(head) {
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nodes.forEach(node => {
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if (node.reversedEdges) {
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node.reversedEdges.forEach(edge => edge.destroy());
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node.reversedEdges = [];
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}
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});
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let current = head;
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while (current !== null && current.right !== null) {
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if (!current.rightEdge) {
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current.rightEdge = createArrow(current, current.right, '#888');
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current.rightEdge.moveToBottom();
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}
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current = current.right;
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}
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nodes.forEach(n => {
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n.shape.moveToTop();
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n.label.moveToTop();
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});
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layer.draw();
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}
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// Reverse a chain of right pointers.
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async function reverseChain(head) {
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updateExplanation("Visualizing the reversal of pointers");
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await waitForNext();
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const reversedHead = await visualizeReversal(head);
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let prev = null, curr = head, next;
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while (curr !== null) {
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next = curr.right;
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curr.right = prev;
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prev = curr;
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curr = next;
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}
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return prev;
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}
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// Restore the chain.
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async function restoreChain(head) {
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updateExplanation("Visualizing the restoration of original pointers");
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await waitForNext();
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await visualizeRestore(head);
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let prev = null, curr = head, next;
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while (curr !== null) {
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next = curr.right;
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curr.right = prev;
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@@ -314,19 +495,15 @@
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// Reverse traverse the right edge of a subtree.
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async function reverseTraverseRightEdge(head) {
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if (!head) return;
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updateExplanation("Reversing the right edge starting from node " + head.val);
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await waitForNext();
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let tail = reverseChain(head);
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let tail = await reverseChain(head);
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layer.draw();
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updateExplanation("Visiting nodes along the reversed right edge");
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let cur = tail;
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while (cur !== null) {
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highlightNode(cur, '#4caf50');
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layer.draw();
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appendOutput(cur.val + " ");
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updateExplanation("Visited node: " + cur.val);
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await waitForNext();
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@@ -334,58 +511,50 @@
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layer.draw();
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cur = cur.right;
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}
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updateExplanation("Restoring the original right edge");
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await waitForNext();
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reverseChain(tail);
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await restoreChain(tail);
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layer.draw();
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}
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// Morris Post‑Order Traversal Animation.
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async function postorderTraversal(root) {
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let current = root;
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while (current !== null) {
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highlightNode(current, '#ffeb3b');
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layer.draw();
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if (current.left !== null) {
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updateExplanation("Current: " + current.val + " - Has left child, finding rightmost node in left subtree");
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updateExplanation("Current: " + current.val + " - Has left child, finding rightmost in left subtree");
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await waitForNext();
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let rightmost = current.left;
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highlightNode(rightmost, '#2196f3');
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layer.draw();
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while (rightmost.right !== null && rightmost.right !== current) {
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updateExplanation("Moving to the right to find rightmost: " + rightmost.val);
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updateExplanation("Moving to right: " + rightmost.val);
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await waitForNext();
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unhighlightNode(rightmost, 'white');
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rightmost = rightmost.right;
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highlightNode(rightmost, '#2196f3');
|
||||
layer.draw();
|
||||
}
|
||||
|
||||
if (rightmost.right === null) {
|
||||
updateExplanation("Rightmost: " + rightmost.val + " - Creating thread to current: " + current.val);
|
||||
await waitForNext();
|
||||
|
||||
createThreadEdge(rightmost, current);
|
||||
rightmost.right = current;
|
||||
highlightNode(rightmost, '#03a9f4');
|
||||
layer.draw();
|
||||
|
||||
await waitForNext();
|
||||
unhighlightNode(rightmost, 'white');
|
||||
unhighlightNode(current, 'white');
|
||||
current = current.left;
|
||||
} else {
|
||||
updateExplanation("Thread detected at rightmost: " + rightmost.val + " - Processing subtree");
|
||||
updateExplanation("Thread detected at rightmost: " + rightmost.val + " - Removing thread and processing subtree");
|
||||
await waitForNext();
|
||||
|
||||
removeThreadEdge(rightmost);
|
||||
rightmost.right = null;
|
||||
unhighlightNode(rightmost, 'white');
|
||||
layer.draw();
|
||||
|
||||
await reverseTraverseRightEdge(current.left);
|
||||
unhighlightNode(current, 'white');
|
||||
current = current.right;
|
||||
@@ -393,25 +562,25 @@
|
||||
} else {
|
||||
updateExplanation("Current: " + current.val + " - No left child, moving right");
|
||||
await waitForNext();
|
||||
|
||||
unhighlightNode(current, 'white');
|
||||
current = current.right;
|
||||
}
|
||||
}
|
||||
|
||||
updateExplanation("Processing final right edge");
|
||||
await waitForNext();
|
||||
|
||||
await reverseTraverseRightEdge(root);
|
||||
updateExplanation("Morris Post-Order Traversal complete");
|
||||
|
||||
await waitForNext();
|
||||
updateExplanation("Final post-order traversal result: " + document.getElementById('output').innerText);
|
||||
nodes.forEach(n => {
|
||||
n.shape.moveToTop();
|
||||
n.label.moveToTop();
|
||||
});
|
||||
layer.draw();
|
||||
}
|
||||
|
||||
// Adjust stage on window resize.
|
||||
window.addEventListener('resize', function() {
|
||||
stage.width(document.querySelector('.tree-container').clientWidth - 40);
|
||||
stage.width(document.querySelector('.tree-container').clientWidth - 30);
|
||||
stage.height(document.querySelector('.tree-container').clientHeight - 140);
|
||||
layer.draw();
|
||||
});
|
||||
|
||||
Reference in New Issue
Block a user