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Description

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.

思路

題意：給出兩棵二叉搜索樹，判斷這兩棵二叉搜索樹是否相同

題解：前序遍歷+中序遍歷或後序遍歷+中序遍歷可以完全確定一顆二叉搜索樹（數據中第52組：[1,null,1] [1,1]，此種寫法掛在了這裏）；或者直接遞歸搜索的過程判斷。

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    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;
    }
}

[LeetCode] 100. Same Tree