LeetCode--Same Tree

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.

分析：

　　判断两个二叉树是否相等。

/**
 * 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;
        if(p==null&&q!=null||p!=null&&q==null) return false;
        return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right)&&(p.val==q.val);
        
        }
}

最后一句分开写的话：

/**
 * 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) {
        boolean left;
        boolean right;
        if(p==null&&q==null) return true;
        if(p==null&&q!=null||p!=null&&q==null) return false;
        if(p.val==q.val){
            left = isSameTree(p.left,q.left);
            right = isSameTree(p.right,q.right);
        }else{
            return false;
        }
        return left&&right;
        
        }
}