Same Tree
题目详情:
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.
解题方法:
判断两颗二叉树是否相等,第一部判断两颗二叉树是否都为空,如果都为空,则return true,如果一个为空一个不为空则return false。第二部两棵树都不为空,比较其元素,若不相等则return false。第三部,如果相等,则比较其左子树,若其左子树不相等,返回false,若相等则比较其右子树,结果return 其右子树是否为空。
代码详情:
/**
* Definition for a binary tree node.
* 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) {
if (p == NULL && q == NULL) {
return true;
} else if (p == NULL && q != NULL) {
return false;
} else if (p != NULL && q == NULL) {
return false;
} else {
if (p->val != q->val) {
return false;
} else{
if (!isSameTree(p->left, q->left)) {
return false;
} else {
return isSameTree(p->right, q->right);
}
}
}
}
};
* Definition for a binary tree node.
* 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) {
if (p == NULL && q == NULL) {
return true;
} else if (p == NULL && q != NULL) {
return false;
} else if (p != NULL && q == NULL) {
return false;
} else {
if (p->val != q->val) {
return false;
} else{
if (!isSameTree(p->left, q->left)) {
return false;
} else {
return isSameTree(p->right, q->right);
}
}
}
}
};