Description:
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.
判断两棵树是不是相等。考虑null的情况。
/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public boolean isSameTree(TreeNode p, TreeNode q) {
if(p==null && q==null)
return true;
else if(p==null&&q!=null || p!=null&&q==null)
return false;
else {
if(p.val != q.val)
return false;
else {
return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
}
}
}
}