100. Same Tree

题目：

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.

链接： http://leetcode.com/problems/same-tree/

一刷

class Solution(object):
    def isSameTree(self, p, q):

        if not p and not q:
            return True
        if not p or not q:
            return False
        
        return p.val == q.val and self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)

2/16/2017, Java, 冒险刷

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;
        
        if (p.val != q.val) return false;
        if (!isSameTree(p.left, q.left)) return false;
        if (!isSameTree(p.right, q.right)) return false;
        return true;
    }    
}