leetcode/0101-symmetric-tree.cpp at master · rustykitty/leetcode · GitHub

Name: leetcode/0101-symmetric-tree.cpp at master · rustykitty/leetcode · GitHub
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/*
101. Symmetric Tree

Submitted: December 9, 2024

Runtime: 0 ms (beats 100.00%)
Memory: 18.41 MB (beats 12.19%)
*/

/**
 * 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) {}
 * };
*/
classSolution {
public:
boolisSymmetric(TreeNode* root) {
if (root == nullptr) returntrue;
returnhelper(root->left, root->right);
 }
boolhelper(TreeNode* a, TreeNode* b) {
if (a == nullptr || b == nullptr) return a == b;
if (a->val != b->val) returnfalse;
returnhelper(a->left, b->right) && helper(a->right, b->left);
 }
};