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.

/**

 * 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){

            if(p.val == q.val){

                boolean x = isSameTree(p.left,q.left);

                boolean y = isSameTree(p.right,q.right);

                return x==true && y==true;

            }

        }

        return false;

    }

}

第一次把判断条件写错了 

return x==true && y==true;

写成了

return x == y;