Binary-Tree-ZigZag-Level-Order-Traversal

C++/Binary-Tree-Zigzag-Level-Order-Traversal.cpp

@@ -0,0 +1,64 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ * int val;
+ * TreeNode *left;
+ * TreeNode *right;
+ * TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+ vector<vector<int>> zigzagLevelOrder(TreeNode* root) {
+ vector<vector<int>> finalvec;
+ int flag = 1;
+ TreeNode *t;
+ stack<TreeNode*>s1;
+ stack<TreeNode*>s2;
+ if(root==NULL)
+ return finalvec;
+ s1.push(root);
+ // vector<int>temp;
+ // temp.push_back(root->val);
+ // finalvec.push_back(temp);
+ while(!s1.empty() || !s2.empty())
+ {
+ if(flag == 1)
+ {
+ vector<int>temp;
+ while(!s1.empty())
+ {
+ t = s1.top();
+ s1.pop();
+ temp.push_back(t->val);
+ if(t->left)
+ s2.push(t->left);
+ if(t->right)
+ s2.push(t->right);
+
+ }
+ finalvec.push_back(temp);
+ flag = 0;
+ }
+ else
+ {
+ vector<int>temp;
+ while(!s2.empty())
+ {
+ t = s2.top();
+ s2.pop();
+ temp.push_back(t->val);
+ if(t->right)
+ s1.push(t->right);
+ if(t->left)
+ s1.push(t->left);
+
+ }
+ finalvec.push_back(temp);
+ flag = 1;
+ }
+ }
+
+ return finalvec;
+ }
+};

README.md

@@ -179,6 +179,7 @@ Check out ---> [Sample PR](https://github.com/codedecks-in/LeetCode-Solutions/pu
 | 129 | [Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/) | [Java](./Java/sum-root-to-leaf-numbers.java) | _O(n)_ | _O(logn)_ | Medium | Binary Tree, Depth First Search | |
 | 307 | [Range Sum Query - Mutable](https://leetcode.com/problems/range-sum-query-mutable/) | [Java](./Java/Range-Sum-Query-Mutable.java) | _O(logn)_ | _O(n)_ | Medium | Segment Tree | |
 | 919 | [Complete Binary Tree Inserter](https://leetcode.com/problems/complete-binary-tree-inserter/) | [Java](./Java/complete-binary-tree-inserter.java) | _O(n)_ | _O(n)_ | Medium | Tree | |
+| 103 | [Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/) | [C++](./C++/binary-tree-preorder-traversal.java) | _O(n)_ | _O(n)_ | Medium | Binary Tree, Stack 
 
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