【LeetCode】100. Same Tree 解题报告

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Subject

出处：https://leetcode.com/problems/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.

Explain

判断两个二叉树是否一样（结构一样，每个对应的结点的值也是一样）。

Solution

solution 1

递归遍历

    /**
     * 0ms
     * 
     * @param p
     * @param q
     * @return
     */
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p == null & q == null) {
            return true;
        }
        if (p == null || q == null) {
            return false;
        }
        if (p.val == q.val) {
            return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
        } else {
            return false;
        }
    }

方法简单死了~

solution 2

https://leetcode.com/discuss/69708/one-line-java-solution

public boolean isSameTree2(TreeNode p, TreeNode q) {
        return (p != null && q != null && p.val == q.val
                && isSameTree2(p.left, q.left) && isSameTree2(p.right, q.right))
                || (p == null && q == null);
    }

该方法只是方法一的变形。虽然只是一句话，但是没有方法一结构清晰。

bingo~~