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SymmetricTree.cpp
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SymmetricTree.cpp
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/*
Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).
For example, this binary tree is symmetric:
1
/ \
2 2
/ \ / \
3 4 4 3
But the following is not:
1
/ \
2 2
\ \
3 3
*/
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
struct TreeNode
{
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
class Solution {
public:
bool isSymmetric(TreeNode* root) {
bool result = false;
if(root == NULL){
return true;
} else{
result = ifSymmetric(root -> left, root -> right);
}
return result;
}
bool ifSymmetric(TreeNode *p, TreeNode *q){
bool result = false;
if(p == NULL && q == NULL){
return true;
} else if(p == NULL || q == NULL){
return false;
} else{
if(p -> val != q -> val){
return false;
} else{
result = ifSymmetric(p -> left, q -> right) && ifSymmetric(p -> right, q -> left);
if(result == false){
return false;
}
}
}
return result;
}
};