Data-Structures-and-Algorithms/Trees/binary-tree-zigzag-level-order-traversal.cpp at main · codemistic/Data-Structures-and-Algorithms · GitHub

Name: Data-Structures-and-Algorithms/Trees/binary-tree-zigzag-level-order-traversal.cpp at main · codemistic/Data-Structures-and-Algorithms · GitHub
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#include<bits/stdc++.h>

usingnamespacestd;

/**
 * Question Link:- https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/
 * Definition for a binary tree node.
 * struct TreeNode {
 * int val;
 * TreeNode *left;
 * TreeNode *right;
 * TreeNode() : val(0), left(nullptr), right(nullptr) {}
 * TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
*/

structTreeNode {
int val;
 TreeNode *left;
 TreeNode *right;
TreeNode() : val(0), left(nullptr), right(nullptr) {}
TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 };

classSolution {
public:
 vector<vector<int>> zigzagLevelOrder(TreeNode* root) {

 vector<vector<int>> ans;
if(!root) return ans;

 queue<TreeNode*> q;

 q.push(root);
bool flag =false;

while(!q.empty()){
int size = q.size();
 vector<int> level;

for(int i=0;i<size;i++){

 TreeNode* node = q.front();
 q.pop();

 level.push_back(node->val) ;

if(node->left) q.push(node->left);
if(node->right) q.push(node->right);


 }


 flag = !flag;
if(flag == false)
reverse(level.begin() , level.end()) ;


 ans.push_back(level) ;


 }
return ans;

 }
};