100. Same Tree

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题目

Given the roots of two binary trees p and q, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical, and the nodes have the same value.

Example 1:

Input: p = [1,2,3], q = [1,2,3]

Output: true

Example 2:

Input: p = [1,2], q = [1,null,2]

Output: false

Example 3:

Input: p = [1,2,1], q = [1,1,2]

Output: false

Constraints:

• The number of nodes in both trees is in the range [0, 100].
• -10^4 <= Node.val <= 10^4

题目大意

这一题要求判断两颗树是否是完全相等的。

如果两个树在结构上相同，并且节点具有相同的值，则认为它们是相同的。

解题思路

递归判断即可。

代码

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