【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.

 

用递归，注意 判断 当 各位NULL的时候的情况。

C++:

class Solution {
public:
    bool isSameTree(TreeNode *p, TreeNode *q) {
        if(p==NULL&&q==NULL) 
            return 1;
        else if(!(q!=NULL&&p!=NULL&&q->val==p->val)) 
            return 0;
        return  isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);
    }
};

 

Python:

class Solution:
    # @param p, a tree node
    # @param q, a tree node
    # @return a boolean
    def isSameTree(self, p, q):
        if p is None and q is None:
            return True
        elif p is None or q is None:
            return False
        else:
            if p.val==q.val:
                if self.isSameTree(q.left,p.left):
                    return self.isSameTree(q.right,p.right)
            return False