adding iterator exercise

lectures/09_iterators_linked_lists/README.md

@@ -162,4 +162,4 @@ also defined.
 ## 9.9 Leetcode Exercises
 
 - [Leetcode problem 27: Remove Element](https://leetcode.com/problems/remove-element/). Solution: [p27_removeelement.cpp](../../leetcode/p27_removeelement.cpp)
-- [Leetcode problem 263: Ugly Number](https://leetcode.com/problems/ugly-number/). Solution: [p263_uglynumber.cpp](../../leetcode/p263_uglynumber.cpp)
+- [Leetcode problem 283: Remove Zeroes](https://leetcode.com/problems/move-zeroes/). Solution: [p283_movezeroes.cpp](../../leetcode/p283_movezeroes.cpp)

leetcode/p283_movezeroes.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+    void moveZeroes(vector<int>& nums) {
+        vector<int>::iterator itr = nums.begin();
+        // use itr2 to represent the "new" vector
+        vector<int>::iterator itr2 = nums.begin();
+        while(itr != nums.end()){
+            // traverse the vector and store all non-zero elements in the "new" vector.
+            if(*itr != 0){
+                *itr2 = *itr;
+                itr2++;
+            }
+            itr++;
+        }
+        // as we skipped zeroes above, we now fill them in.
+        while(itr2!=nums.end()){
+            *itr2 = 0;
+            itr2++;
+        }
+    }
+};