Same Tree

Same Tree 

问题：

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.

思路：

递归

我的方法：

public class Solution {

    public boolean isSameTree(TreeNode p, TreeNode q) {

        if(p == null && q == null)

            return true ;

        else if(p == null && q != null)

            return false ;

        else if(p != null && q == null)

            return false ;

        else

            return (p.val == q.val) && isSameTree(p.left, q.left) && isSameTree(p.right, q.right) ;

    }

}

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别人方法：

public class Solution {

    public boolean isSameTree(TreeNode p, TreeNode q) {

        if (p == null && q == null) return true;

        if (p == null || q == null || p.val != q.val) return false;

        return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);

    }

}

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