Tonix - 博客园

LeetCode "Gas Station" - TO BE REVISED

摘要： First I thought of a DP solution.. but TLE. So there must be a O(n). I thought of Mono-Queue.. but looks too complex.So what is the naive solution? O(... 阅读全文

posted @ 2014-08-21 13:23 Tonix 阅读(172) 评论(0) 推荐(0)

LeetCode "Median of Two Sorted Arrays"

摘要： 1A! We get median of each array and compare them, then we know which half should be disguarded and how many should be disguarded.class Solution {publi... 阅读全文

posted @ 2014-08-21 12:09 Tonix 阅读(162) 评论(0) 推荐(0)

LeetCode "Distinct Subsequences" - TO BE REVISED

摘要： A classic and representative DP problem. To be revised later. Quite a few interesting details to think about.class Solution {public: int numDistinc... 阅读全文

posted @ 2014-08-21 11:28 Tonix 阅读(138) 评论(0) 推荐(0)

LeetCode "Permutation Sequence"

摘要： 1A! This is actually a basic question in Combinatorics: if at digit[k] = n, it contributes (k-1)! * n to the targeted index.class Solution {public: ... 阅读全文

posted @ 2014-08-19 13:26 Tonix 阅读(148) 评论(0) 推荐(0)

懒

摘要：找到自己切题的主要障碍了：试图刚读完题就foresee到最后的solution，其实就是妄图利用比较省事的感性直接超越逻辑推导的理性：其实就是懒。超验感性实际上是建立在大量理性的思考与实践上的。这话不是我说的，出自一位顶尖数学家之口。更别说偶了。阅读全文

posted @ 2014-08-19 12:40 Tonix 阅读(149) 评论(0) 推荐(0)

LeetCode "Linked List Cycle II"

摘要： Nothing but admire: http://fisherlei.blogspot.com/2013/11/leetcode-linked-list-cycle-ii-solution.htmlclass Solution {public: ListNode *detectCycle(... 阅读全文

posted @ 2014-08-19 12:36 Tonix 阅读(143) 评论(0) 推荐(0)

LeetCode "Best Time to Buy and Sell Stock III"

摘要： Refer: http://blog.unieagle.net/2012/12/05/leetcode%E9%A2%98%E7%9B%AE%EF%BC%9Abest-time-to-buy-and-sell-stock-iii%EF%BC%8C%E4%B8%80%E7%BB%B4%E5%8A%A8%... 阅读全文

posted @ 2014-08-19 11:42 Tonix 阅读(178) 评论(0) 推荐(0)

LeetCode "4Sum"

摘要： Similar strategy could be applied to 4Sum, as 2sum to 3sum, but that'll be O(n^3). Instead of 3 + 1, we can also divide it into 2 + 2. So the problem ... 阅读全文

posted @ 2014-08-18 12:23 Tonix 阅读(187) 评论(0) 推荐(0)

LeetCode "3Sum closest"

摘要： Simply a variation of 3Sum:class Solution {public: int threeSumClosest(vector &num, int target) { int ret = 99999999999; std::sort(nu... 阅读全文

posted @ 2014-08-18 10:39 Tonix 阅读(138) 评论(0) 推荐(0)

LeetCode "3Sum"

摘要： Now that you've solved 2sum, 3sum can be easily converted as 2sum.Also please note the while loops for i1 and i2: they are to make sure no duplicates.... 阅读全文

posted @ 2014-08-18 10:12 Tonix 阅读(151) 评论(0) 推荐(0)

LeetCode "Container With Most Water"

摘要： O(n^2) is a naive solution. As rule of thumb, there must be O(n) soluion. Yes - Greedy.We assume widest container contains the most water, greedily, b... 阅读全文

posted @ 2014-08-16 14:38 Tonix 阅读(139) 评论(0) 推荐(0)

Data Structures

摘要： -!5. Trie\Suffix Tree:http://blog.csdn.net/v_july_v/article/details/6897097 Trie: think about how you used King Dict by typing; Suffix Tree: all suff... 阅读全文

posted @ 2014-08-16 14:06 Tonix 阅读(213) 评论(0) 推荐(0)

LeetCode "Sudoku Solver"

摘要： Simply DFS + Backtrace, as N-Queenclass Solution {public: vector> rows; vector> cols; vector>> subboxHm; bool isValid(char c, int i, int j... 阅读全文

posted @ 2014-08-16 06:34 Tonix 阅读(142) 评论(0) 推荐(0)

LeetCode "Valid Sudoku"

摘要： Here another memory for speed implementation:class Solution {public: bool isValidSudoku(vector > &board) { size_t row_cnt = board.size(); ... 阅读全文

posted @ 2014-08-15 12:20 Tonix 阅读(151) 评论(0) 推荐(0)

LeetCode "Candy" - from skill to thought

摘要： Main reference: http://zhaohongze.com/wordpress/2013/12/10/leetcode-candy/I was confused by the constraint on BOTH sides of an element. Strategy is: s... 阅读全文

posted @ 2014-08-15 10:13 Tonix 阅读(247) 评论(0) 推荐(0)

LeetCode "Binary Tree Maximum Path Sum"

摘要： http://yucoding.blogspot.com/2012/12/leetcode-question-13-binary-tree.htmlUsually for tree problems, it is either recursion or traversal. For this one... 阅读全文

posted @ 2014-08-15 08:11 Tonix 阅读(114) 评论(0) 推荐(0)

LeetCode "Largest Rectangle in Histogram" - TRICKY MONO-QUEUE

摘要： I got a DP solution first which is O(n^2). Apparently it is not a optimized one - think about: it is linear value space. There must be O(n) solution.A... 阅读全文

posted @ 2014-08-15 04:48 Tonix 阅读(310) 评论(0) 推荐(0)

LeetCode "LRU Cache"

摘要： 1A. It is a design problem actually. It tests your ability to connect your knowledge of data structures & algorithms, with real world problems.class L... 阅读全文

posted @ 2014-08-14 08:46 Tonix 阅读(167) 评论(0) 推荐(0)

LeetCode "Text Justification"

摘要： Just take care of corner cases!class Solution {public: vector fullJustify(vector &words, int L) { vector ret; int startInx = 0; ... 阅读全文

posted @ 2014-08-13 09:40 Tonix 阅读(143) 评论(0) 推荐(0)

LeetCode "Word Ladder" - TRICKY

摘要： It is not as easy as I thought it to be, mostly because of time\space limitation. And actually that's the punch line of this problemMy intuition was D... 阅读全文

posted @ 2014-08-13 07:30 Tonix 阅读(160) 评论(0) 推荐(0)

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