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Algorithms, Distributed System, Machine Learning
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08 2015 档案

LintCode "Partition Array by Odd and Even"
摘要：One pass in-place solution: all swaps.class Solution {public: /** * @param nums: a vector of integers * @return: nothing */ void partit... 阅读全文
posted @ 2015-08-29 14:38 Tonix 阅读(203) 评论(0) 推荐(0)

LintCode "Continuous Subarray Sum"
摘要：A variation to a classical DP: LCS.class Solution {public: /** * @param A an integer array * @return A list of integers includes the index o... 阅读全文
posted @ 2015-08-29 11:43 Tonix 阅读(207) 评论(0) 推荐(0)

LeetCode "Strobogrammatic Number III"
摘要：It can be solved based on the code from "Strobogrammatic Number II". The idea is pretty straight forward - binary search the boundaries.class Solution... 阅读全文
posted @ 2015-08-29 06:59 Tonix 阅读(170) 评论(0) 推荐(0)

LeetCode "Encode and Decode Strings"
摘要：This is abouthttps://en.wikipedia.org/wiki/Run-length_encoding. The trick is, for a valid char, we only compress up to 254 occurences - count 255 mean... 阅读全文
posted @ 2015-08-29 01:34 Tonix 阅读(315) 评论(0) 推荐(0)

LeetCode "Ugly Number II"
摘要：Key: each of 2\3\5 is trying to multiply with the least number it has not been multiplied.class Solution {public: int nthUglyNumber(int n) { ... 阅读全文
posted @ 2015-08-25 13:15 Tonix 阅读(124) 评论(0) 推荐(0)

LeetCode "Alien Dictionary"
摘要：Another topological sorting problem. Note: the DFS one is like a 'post-order' traversal.class Solution { unordered_map> g; unordered_set visited... 阅读全文
posted @ 2015-08-25 12:44 Tonix 阅读(239) 评论(0) 推荐(0)

LeetCode "3Sum Smaller"
摘要：A variation of 3Sum. And the trick is, (i& nums, int target) { size_t len = nums.size(); if(len = target) k--; ... 阅读全文
posted @ 2015-08-24 14:38 Tonix 阅读(150) 评论(0) 推荐(0)

LeetCode "Group Shifted Strings"
摘要：Use constructive strategy: we compose each of the 26 variations of one word.class Solution {public: vector> groupStrings(vector& strings) { ... 阅读全文
posted @ 2015-08-24 12:26 Tonix 阅读(217) 评论(0) 推荐(0)

LeetCode "Read N Characters Given Read4 II - Call multiple times"
摘要：I learnt a clean idea: all read is from the 4-char buffer.int read4(char *buf);class Solution { int offset; int validLen; char _buf[4]; ... 阅读全文
posted @ 2015-08-24 11:42 Tonix 阅读(157) 评论(0) 推荐(0)

LeetCode "Factor Combinations"
摘要：An interesting DFS with a lot of details to take care of.class Solution { vector> ret; void go(int n, vector sofar, int minF) { int st... 阅读全文
posted @ 2015-08-23 12:43 Tonix 阅读(258) 评论(0) 推荐(0)

LeetCode "Paint House II"
摘要：Classic DP! For house[i] to pick a min-color from dp[i-1], we only need to check if color j is the min cost color index of dp[i - 1]; if yes, then we ... 阅读全文
posted @ 2015-08-23 12:21 Tonix 阅读(233) 评论(0) 推荐(0)

LeetCode "Shortest Word Distance II"
摘要：Simply store indices in ctor.class WordDistance { unordered_map> hm;public: WordDistance(vector& words) { for (int i = 0; i &vec1 = hm[w... 阅读全文
posted @ 2015-08-22 11:18 Tonix 阅读(179) 评论(0) 推荐(0)

LeetCode "Flatten 2D Vector"
摘要：Just take care of corner cases..class Vector2D { vector> &r; int i, i0;public: Vector2D(vector>& vec2d) : r(vec2d), i(0), i0(0) { i... 阅读全文
posted @ 2015-08-22 10:59 Tonix 阅读(180) 评论(0) 推荐(0)

LeetCode "Meeting Rooms II"
摘要：Linear scan after sorting. Please note sorting detail.typedef std::pair Rec;class Solution {public: int minMeetingRooms(vector& intervals) { ... 阅读全文
posted @ 2015-08-22 10:37 Tonix 阅读(182) 评论(0) 推荐(0)

LeetCode "Paint House"
摘要：A typical DPclass Solution {public: int minCost(vector>& costs) { size_t len = costs.size(); if(len == 0) return 0; ve... 阅读全文
posted @ 2015-08-22 00:46 Tonix 阅读(176) 评论(0) 推荐(0)

LeetCode "Longest Substring with At Most Two Distinct Characters"
摘要：A typical sliding window solution.class Solution { int rec[26]; // for a-z int rec1[26]; // for A-Z int cnt; int &getCnt(char c) ... 阅读全文
posted @ 2015-08-21 13:16 Tonix 阅读(125) 评论(0) 推荐(0)

LeetCode "Graph Valid Tree"
摘要：DFS to check cyclic. Please note some details.class Solution{ unordered_map> g; unordered_set visited; bool go(int i, int p) // true - cy... 阅读全文
posted @ 2015-08-21 12:41 Tonix 阅读(260) 评论(0) 推荐(0)

LeetCode "Shortest Word Distance"
摘要：A variation of linear scan..typedef pair Rec;class Solution {public: int shortestDistance(vector& words, string word1, string word2) { v... 阅读全文
posted @ 2015-08-20 15:32 Tonix 阅读(133) 评论(0) 推荐(0)

LeetCode "Verify Preorder Sequence in Binary Search Tree"
摘要：A typical recursion one.class Solution { bool _verify(vector &in, int i, int j, int low, int high) { if (i > j) return tr... 阅读全文
posted @ 2015-08-20 14:59 Tonix 阅读(247) 评论(0) 推荐(0)

LeetCode "Binary Tree Upside Down"
摘要：Recursion, a natural thought:class Solution { // Top : BottomRight std::pair rotate(TreeNode *p) { if (!p->left && !p->right) ... 阅读全文
posted @ 2015-08-20 13:23 Tonix 阅读(169) 评论(0) 推荐(0)

HackerRank - "Candles Counting" - DIFFICULT
摘要：It should be categorized as 'Advanced' I think ... Anyway, Fenwick tree is the key.Editorial:https://www.hackerrank.com/challenges/candles-2/editorial... 阅读全文
posted @ 2015-08-10 13:07 Tonix 阅读(658) 评论(0) 推荐(0)

HackerRank - "Snakes and Ladders: The Quickest Way Up"
摘要：A trickier Dijkstra.#include #include #include #include #include #include #include #include #include using namespace std;const int INF = std::numeric_... 阅读全文
posted @ 2015-08-03 07:41 Tonix 阅读(393) 评论(0) 推荐(0)

HackerRank - "Floyd : City of Blinding Lights"
摘要：Typical Floyd-Walshall Algorithm.#include #include #include #include #include #include #include #include #include using namespace std;const long DIST_... 阅读全文
posted @ 2015-08-03 01:52 Tonix 阅读(331) 评论(0) 推荐(0)

HackerRank "Dijkstra: Shortest Reach 2"
摘要：No big difference with "Breadth First Search: Shortest Reach", but this statement is crucial:If there are edges between the same pair of nodes with di... 阅读全文
posted @ 2015-08-02 15:18 Tonix 阅读(1175) 评论(0) 推荐(0)

HackerRank - "Breadth First Search: Shortest Reach"
摘要：Typical Dijstra algorithm impl. one.#include #include #include #include #include #include #include #include #include using namespace std;const long DI... 阅读全文
posted @ 2015-08-02 14:43 Tonix 阅读(1189) 评论(0) 推荐(0)

HackerRank - "Lego Blocks"
摘要：A combination of different DP passes.https://www.hackerrank.com/challenges/lego-blocks/editorial#include #include #include using namespace std;typedef... 阅读全文
posted @ 2015-08-02 05:31 Tonix 阅读(866) 评论(0) 推荐(0)

LeetCode "Different Ways to Add Parentheses"
摘要：My initial thought was recursive (a op b) evaluation, which doesn't work quite well.The correct way is to split by op. And, we can cache calculaton re... 阅读全文
posted @ 2015-08-01 13:45 Tonix 阅读(147) 评论(0) 推荐(0)