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// 101. Symmetric Tree
#include <stdbool.h>
#include <stddef.h>
// given 'root' of binary tree, check whether it is a mirror of itself
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
};
bool traverse(struct TreeNode *left, struct TreeNode *right) {
if (left == NULL && right == NULL)
return true;
if (left == NULL || right == NULL)
return false;
if (left->val != right->val)
return false;
return traverse(left->left, right->right) &&
traverse(left->right, right->left);
}
bool isSymmetric(struct TreeNode *root) {
if (root == NULL)
return true;
return traverse(root->left, root->right);
}
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