LeetCode100. Same Tree 解题报告

Posted 2020-07-19 月盡天明

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转载请注明出处：http://blog.csdn.net/crazy1235/article/details/51541570

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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.

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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）。

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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~

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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。

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bingo~~