111 lines
2.3 KiB
C++
111 lines
2.3 KiB
C++
#include <iostream>
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#include <vector>
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#include <queue>
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// Definition for a binary tree node.
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class TreeNode {
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public:
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int val;
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TreeNode* left;
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TreeNode* right;
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TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
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};
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std::vector<std::vector<int>> levelOrderTraversal(TreeNode* root) {
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std::vector<std::vector<int>> result;
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if (root == nullptr) {
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return result;
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}
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std::queue<TreeNode*> myQueue;
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myQueue.push(root);
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while (!myQueue.empty()) {
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int size = myQueue.size();
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std::vector<int> current_level;
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for (int i = 0; i < size; i++) {
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TreeNode* current = myQueue.front();
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myQueue.pop();
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std::cout << current->val << " ";
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if (current != nullptr) {
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current_level.push_back(current->val);
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if (current->left != nullptr) {
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myQueue.push(current->left);
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}
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if (current->right != nullptr) {
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myQueue.push(current->right);
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}
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}
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}
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result.push_back(current_level);
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}
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return result;
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}
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int main() {
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/* test case 1
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* 1
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* 2 3
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* 4 5 6 7
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*/
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TreeNode* root1 = new TreeNode(1);
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root1->left = new TreeNode(2);
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root1->right = new TreeNode(3);
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root1->left->left = new TreeNode(4);
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root1->left->right = new TreeNode(5);
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root1->right->left = new TreeNode(6);
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root1->right->right = new TreeNode(7);
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std::cout << "Level Order Traversal: ";
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levelOrderTraversal(root1);
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std::cout << std::endl;
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/* test case 2
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* 1
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* 2 3
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* 4 5 6 7
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* 8 9
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*/
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TreeNode* root2 = new TreeNode(1);
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root2->left = new TreeNode(2);
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root2->right = new TreeNode(3);
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root2->left->left = new TreeNode(4);
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root2->left->right = new TreeNode(5);
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root2->right->left = new TreeNode(6);
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root2->right->right = new TreeNode(7);
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root2->right->right->left = new TreeNode(8);
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root2->right->right->right = new TreeNode(9);
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std::cout << "Level Order Traversal: ";
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levelOrderTraversal(root2);
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std::cout << std::endl;
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/* test case 3
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* 1
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* 2 3
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* 4 5 6 7
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* 8
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*/
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TreeNode* root3 = new TreeNode(1);
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root3->left = new TreeNode(2);
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root3->right = new TreeNode(3);
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root3->left->left = new TreeNode(4);
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root3->left->right = new TreeNode(5);
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root3->right->left = new TreeNode(6);
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root3->right->right = new TreeNode(7);
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root3->left->left->left = new TreeNode(8);
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std::cout << "Level Order Traversal: ";
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levelOrderTraversal(root3);
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std::cout << std::endl;
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return 0;
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}
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