Unique Binary Search Trees:求生成二叉排序树的个数. Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 算法分析:类似…

Unique Binary Search Trees Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 思路: f(n) = Σi=1n f(…

Unique Binary Search Trees Total Accepted: 69271 Total Submissions: 191174 Difficulty: Medium Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3…

Unique Binary Search Trees Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 Unique Binary Search…

1. Unique Binary Search Trees 题目链接 题目要求: Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 题目分析参…

1.二叉搜索树:去一个陌生的城市问路到目的地: for each node, all elements in its left subtree are less-or-equal to the node (<=), and all the elements in its right subtree are greater than the node (>). 给予一个已经排序好的整数数组, 生成一个相对合理的二叉搜索树.(?相对合理的?) 给予一个二叉树的根节点,验证该树是否是二叉树搜索树,(…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 这道题实际上是Catalan Number卡塔兰数的一个例子,如果对卡塔兰数不熟悉的童鞋可能真…

Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 confused what "{1,#,2…

Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example, Given n = 3, your program should return all 5 unique BST's shown below. 1               3            3             2             1 \          …

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, given n = 3, there are a total of 5 unique BST's. 1         3     3      2      1     \       /     /      / \      \      3     2     1      1  …

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 Tree Dynamic Programming     如果集合为空,只有一种BST,即空树…

Unique Binary Search Trees II Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \…

本题利用BST的特性来用DP求解.由于BST的性质,所以root左子树的node全部<root.而右子树的node全部>root. 左子树 = [1, j-1], root = j, 右子树 = [j+1, n] dp[n] = sum(dp[j - 1] * dp[n - j - 1]) def numTrees(self, n): """ :type n: int :rtype: int """ dp = [0]*(n+1) dp…

Unique Binary Search Trees Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3   推导出递推公式即可: 对于1个元素来…

Unique Binary Search Trees II Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \…

Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 这次的题目要求是得到所有的树. 我的思路:…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 题目的的意思是给出n个节点,求出有多少不同的二叉树,实际是计算卡特兰数可以参考二叉树.卡特兰数…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, Given n = 3, there are a total of 5 unique BST's. 看得别人的代码,然后写出来的 :http://www.2cto.com/kf/201312/262420.html public class UniqueBinarySearchTrees {…

Unique Binary Search Trees II Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example, Given n = 3, your program should return all 5 unique BST's shown below. 1         3     3      2      1 \      …

Description: Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 和第I题的区别是…

Description: Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 问题大意:给一个整数n,计算出节点数为n的二叉查找树的种类. 这个题…

题目: Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example, Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 思路: 仍和Unique Bin…

题目: Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 思路: 找规律 1. 没有节点,BST (Binary Search Tree)为1…

LeetCode:Unique Binary Search Trees Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 分析:依次把每个节点作…

Given n, how many structurally unique BSTs (binary search trees) that store values 1...n? Example Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 分析: 当数组为 1,2,3,4,.. i,.. n时,基于以下原则的BST建树具有唯一性:以i为根节点…

题目: Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 思路: 本题采取递归的思路. 传递的参数是开始数值(begin)和结束数值(end). 当begin > end 时,返回空(注意不是…

题目: Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 思路: 需要使用递推关系来解决. 对于n个结点,除去根节点,还剩余n-1个结点. 因此左右子树的结点数分配方式如下所示: (0,n-1), (1,n-2), (2, n-3), ....…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 Summary: dynamic programming int numTrees(int n…

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3   思路: 遇到二叉树,多半是分为左右子树两个问题递归下去. 由序列[1,…,m]和[i+1,…

Given an integer n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 是第96题的延伸,要…