【LeetCode从零单刷】Same Tree
2015-04-07 20:00
302 查看
没错我就是伍声2009的粉丝,从今天起,模仿《从零单排》系列,菜鸡单刷LeetCode!
题目:
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.
解答:
验证两棵树是否相等。使用递归的思想,如果树节点的val相等,则去各自计算子树是否是相等的树。
注意递归终点:输入的两棵树全部都是空树时,输出 true. 所以我得到了这个:
/**
* 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) {
if(p == NULL && q == NULL)
return true;
else if(p->val == q->val)
return (isSameTree(p->left, q->left) && isSameTree(p->right, q->right));
else
return false;
}
};好吧没有通过……当输入空树,与一棵非空树比较时,空树根本无法取到 val 值。所以要将输入空树的情况首先(如果放到以后的分支中,还是会遇到空树求值的情况)全部排除。得到:
/**
* 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) {
if(p == NULL && q == NULL)
return true;
else if((p==NULL && q!=NULL) || (q==NULL && p!=NULL) || (p->val != q->val))
return false;
else if(p->val == q->val)
return (isSameTree(p->left, q->left) && isSameTree(p->right, q->right));
}
};
题目:
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.
解答:
验证两棵树是否相等。使用递归的思想,如果树节点的val相等,则去各自计算子树是否是相等的树。
注意递归终点:输入的两棵树全部都是空树时,输出 true. 所以我得到了这个:
/**
* 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) {
if(p == NULL && q == NULL)
return true;
else if(p->val == q->val)
return (isSameTree(p->left, q->left) && isSameTree(p->right, q->right));
else
return false;
}
};好吧没有通过……当输入空树,与一棵非空树比较时,空树根本无法取到 val 值。所以要将输入空树的情况首先(如果放到以后的分支中,还是会遇到空树求值的情况)全部排除。得到:
/**
* 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) {
if(p == NULL && q == NULL)
return true;
else if((p==NULL && q!=NULL) || (q==NULL && p!=NULL) || (p->val != q->val))
return false;
else if(p->val == q->val)
return (isSameTree(p->left, q->left) && isSameTree(p->right, q->right));
}
};
相关文章推荐
- leetcode Same Tree
- leetcode: Same Tree
- 【LeetCode】Maximum Depth of Binary Tree&&Same Tree
- [LeetCode]Same Tree
- 100. Same Tree Leetcode Python
- LeetCode Same Tree
- leetcode -- Same Tree -- 简单重点
- leetcode: Same Tree (C++)
- leetcode Same Tree
- Leetcode Same Tree
- 【LeetCode从零单刷】Convert Sorted List to Binary Search Tree
- leetcode解题之100# Same Tree Java版
- leetcode 虐我篇之(十九)Same Tree
- LeetCode: Same Tree
- LeetCode之Same Tree
- LeetCode: Same Tree [100]
- [LeetCode] 093: Same Tree
- LeetCode:Same Tree
- LeetCode Same Tree OJ 算法 刷题
- LeetCode: Same Tree