Lemonade Change
这题不难，核心是找零问题，首先看下题目： At a lemonade stand, each lemonade costs $5. Customers are standing in a queue ...
Buddy Strings
我又回来了，继续刷算法，可能的话，英文也想加强一下。由于好久没有刷了，先把新增的几个easy级别题目做了。首先看下面这题： Given two strings A and B of lowercase...
wiggle sequence
这题没有做过类似的，所以感觉还是有点难度的，先来看下题目： A sequence of numbers is called a wiggle sequence if the differences b...
Largest Divisible Subset
Given a set of distinct positive integers, find the largest subset such that every pair (Si, Sj) of ...
House Robber III
The thief has found himself a new place for his thievery again. There is only one entrance to this a...
Unique Binary Search Trees
Given n, how many structurally unique BST’s (binary search trees) that store values 1 …...
Unique Binary Search Trees II
Given an integer n, generate all structurally unique BST’s (binary search trees) that store va...
Increasing Triplet Subsequence
这题挺有意思，主要是要找出是否有3个元素递增，这3个元素的索引必须依次增加但是不要求临近。首先贴题目： Given an unsorted array return whether an increa...
Wiggle Sort II
这题的follow up实在太难，没想出来，就贴一个简单的做法。首先先贴一下题目： Given an unsorted array nums , reorder it such that nums[0...
Longest Increasing Subsequence
这题我做的时候用了动态规划，但是也只是能满足时间复杂度小于O(N2)，先看下题目 Given an unsorted array of integers, find the length of lon...