Symmetric Tree Problem


Description

LeetCode Problem 101.

Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).

Example 1:

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Input: root = [1,2,2,3,4,4,3]
Output: true

Example 2:

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Input: root = [1,2,2,null,3,null,3]
Output: false

Constraints:

  • The number of nodes in the tree is in the range [1, 1000].
  • -100 <= Node.val <= 100


Sample C++ Code

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class Solution {
public:
    bool isMirror(TreeNode* t1, TreeNode* t2) {
        if ((t1 == NULL) && (t2 == NULL))
            return true;
        else if (t1 == NULL)
            return false;
        else if (t2 == NULL)
            return false;
        else
            return (
                (t1->val == t2->val) && 
                isMirror(t1->left, t2->right) && 
                isMirror(t1->right, t2->left)
            );
    }
    
    bool isSymmetric(TreeNode* root) {
        return isMirror(root, root);
    }
};




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