[LeetCode] Same Tree

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

用树的遍历来检查。

/**
* Definition for binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
bool isSameTree(TreeNode *p, TreeNode *q) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
if (p == NULL && q == NULL)
return true;

if (p == NULL || q == NULL)
return false;

bool leftSame = isSameTree(p->left, q->left);
bool rightSame = isSameTree(p->right, q->right);

return leftSame && rightSame && p->val == q->val;
}
};