2015年6月25日
[LeetCode] Minimum Size Subarray Sum
摘要： The problem statement has stated that there are bothO(n)andO(nlogn)solutions to this problem. Let's see theO(n)solution first (taken fromthis link), w... 阅读全文
posted @ 2015-06-25 17:33 jianchao-li 阅读(228) 评论(0) 推荐(0) 编辑
[LeetCode] Reverse Words in a String II
摘要： Problem Description:Given an input string, reverse the string word by word. A word is defined as a sequence of non-space characters.The input string d... 阅读全文
posted @ 2015-06-25 16:56 jianchao-li 阅读(237) 评论(0) 推荐(0) 编辑
[LeetCode] Repeated DNA Sequences
摘要： This link has a great discussion about this problem. You may refer to it if you like. In fact, the idea and code in this passage is from the former li... 阅读全文
posted @ 2015-06-25 15:28 jianchao-li 阅读(774) 评论(0) 推荐(0) 编辑
[LeetCode] Word Ladder
摘要： Well, this problem has a nice BFS structure.Let's see the example in the problem statement.start = "hit"end = "cog"dict = ["hot", "dot", "dog", "lot",... 阅读全文
posted @ 2015-06-25 01:00 jianchao-li 阅读(310) 评论(0) 推荐(0) 编辑
2015年6月24日
[LeetCode] Surrounded Regions
摘要： This problem is not quite difficult (a typical BFS traversal of graph), though, its aceptance rate is relatively low. In fact, the key obstacle in pas... 阅读全文
posted @ 2015-06-24 19:09 jianchao-li 阅读(222) 评论(0) 推荐(0) 编辑
[LeetCode] Clone Graph
摘要： This problem is an application of graph traversal, which has two systematic methods:Bread-First Search (BFS)andDepth-First Search (DFS). In the follow... 阅读全文
posted @ 2015-06-24 16:03 jianchao-li 阅读(198) 评论(0) 推荐(0) 编辑
[LeetCode] Gas Station
摘要： To solve this problem, some observations have to be made first.Let's first see two relatively easy observations.To maximize the probability that we ca... 阅读全文
posted @ 2015-06-24 00:51 jianchao-li 阅读(354) 评论(0) 推荐(0) 编辑
2015年6月23日
[LeetCode] Number of Islands
摘要： This is a typical problem aboutsearching. In fact, you can use either BFS or DFS for it. Personally, I use BFS because I think it is more intuitive an... 阅读全文
posted @ 2015-06-23 20:25 jianchao-li 阅读(227) 评论(0) 推荐(0) 编辑
2015年6月22日
[LeetCode] Basic Calculator II
摘要： The basic idea of is as follows:Maintain a dequeoperandsfor the numbers and another dequeoperationsfor the operators+, -, *,/`.Scan the expression fro... 阅读全文
posted @ 2015-06-22 23:27 jianchao-li 阅读(307) 评论(0) 推荐(0) 编辑
[POJ] Brackets Sequence
摘要： This problem can be solved elegantly using dynamic programming.We maintain two arrays:cnt[i][j] --- number of parentheses needed to add within s[i..j]... 阅读全文
posted @ 2015-06-22 17:58 jianchao-li 阅读(219) 评论(0) 推荐(0) 编辑
2015年6月19日
[Algorithms] KMP
摘要： KMP is a classic and yet notoriously hard-to-understand algorithm. However, I think the following two links give nice explanations. You may refer to t... 阅读全文
posted @ 2015-06-19 15:25 jianchao-li 阅读(262) 评论(0) 推荐(0) 编辑
2015年6月18日
[LeetCode] Combination Sum
摘要： Well, a typical backtracking problem. Make sure you are clear with the following three problems:What is a partial solution and when is it finished? --... 阅读全文
posted @ 2015-06-18 00:23 jianchao-li 阅读(196) 评论(0) 推荐(0) 编辑
2015年6月16日
[LeetCode] Letter Combinations of a Phone Number
摘要： Well, a typical backtracking problem. Make sure you are clear with the following three problems:What is a partial solution and when is it finished? --... 阅读全文
posted @ 2015-06-16 23:57 jianchao-li 阅读(250) 评论(0) 推荐(0) 编辑
[LeetCode] Combinations
摘要： A typical backtracking problem. For any backtracking problem, you need to be think about three ascepts:What is a partial solution and when is it finis... 阅读全文
posted @ 2015-06-16 23:45 jianchao-li 阅读(178) 评论(0) 推荐(0) 编辑
2015年6月15日
[Algorithms] Longest Increasing Subsequence
摘要： The Longest Increasing Subsequence (LIS) problem requires us to find a subsequence t of a given sequence s, such that t satisfies two requirements:Ele... 阅读全文
posted @ 2015-06-15 11:46 jianchao-li 阅读(265) 评论(0) 推荐(0) 编辑