相同的树算法
给你两棵二叉树的根节点 p
和 q
,编写一个函数来检验这两棵树是否相同。
如果两个树在结构上相同,并且节点具有相同的值,则认为它们是相同的。
示例 1:
输入:p = [1,2,3], q = [1,2,3] 输出:true
示例 2:
输入:p = [1,2], q = [1,null,2] 输出:false
示例 3:
输入:p = [1,2,1], q = [1,1,2] 输出:false
提示:
- 两棵树上的节点数目都在范围
[0, 100]
内 -104 <= Node.val <= 104
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
public boolean isSameTree(TreeNode p, TreeNode q) {
return cycleTree(p, q);
}
public boolean cycleTree(TreeNode p, TreeNode q) {
boolean flag = true;
if ((p == null && q != null) || (p != null && q == null)) {
return false;
}
if (p != null && q != null) {
if (p.val == q.val) {
flag = cycleTree(p.left, q.left);
if (!flag) {
return flag;
}
flag = cycleTree(p.right, q.right);
} else {
return false;
}
}
return flag;
}
}