100. Same Tree

题目

Given two binary trees, 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:     1         1
          / \       / \
         2   3     2   3

        [1,2,3],   [1,2,3]

Output: true

Example 2:

Input:     1         1
          /           \
         2             2

        [1,2],     [1,null,2]

Output: false

Example 3:

Input:     1         1
          / \       / \
         2   1     1   2

        [1,2,1],   [1,1,2]

Output: false

题目大意

这一题要求判断 2 颗树是否是完全相等的。

解题思路

递归判断即可。

代码

package leetcode

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func isSameTree(p *TreeNode, q *TreeNode) bool {
	if p == nil && q == nil {
		return true
	} else if p != nil && q != nil {
		if p.Val != q.Val {
			return false
		}
		return isSameTree(p.Left, q.Left) && isSameTree(p.Right, q.Right)
	} else {
		return false
	}
}

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