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Given a binary tree, find the maximum path sum.The path may start and end at any node in the tree. For example: Given the below binary tree,1/ \2 3Ret... 阅读全文
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Thursday, October 23, 2014CodingTMD’s Reading ListFollowing reading list is selected from the papers I had read in the past 3 years. It will help you ... 阅读全文
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#include "stdafx.h"#include using namespace std;static vector alpha;void seq_printer(unsigned int* a, unsigned int* a_end){ for (unsigned int* i = a; i n) { // we want only necklaces, not pre-necklaces or Lyndon words if (n % p == 0) { seq_printer(a + 1, a + p + 1); ... 阅读全文
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Given two words (startandend), and a dictionary, find the length of shortest transformation sequence fromstarttoend, such that:Only one letter can be changed at a timeEach intermediate word must exist in the dictionaryFor example,Given:start="hit"end="cog"dict=["hot",&q 阅读全文
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1.经典的N皇后问题就是个经典的DFS算法我摆到第一行第一列了哦，然后就开始Deep看下一行，可以放哪，然后递推，直到棋盘的行列到。 void NQueenHelper(vector> & board, vector>& result, int row) { int N = board.size(); if (row == N)//reached end scenario { string str; vector final; for (int i = 0; i>& board,... 阅读全文
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Given a stringsand a dictionary of wordsdict, add spaces insto construct a sentence where each word is a valid dictionary word.Return all such possible sentences.For example, givens="catsanddog",dict=["cat", "cats", "and", "sand", "dog"].A 阅读全文
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问题，read()从stream中读出一个字符。然后在stream 中找到含有目标字符串的位置。这个题目是个典型的KMP算法。KMP算法的关键在于如果build Next数组讲KMP算法讲的比较好的网站http://www.ruanyifeng.com/blog/2013/05/Knuth%E2%80%93Morris%E2%80%93Pratt_algorithm.html其实用平实的逻辑思考也能想明白这个算法究竟是怎么来。string S1 abcd......string S2 Ai.....An1. 当拿S2和S1去匹配的时候，当在S2的第K位置发生不匹配的时候，最最naive的方法就 阅读全文
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Given a collection of numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].排列问题，直观的排列问题如{1,2,3} 当第一次位的1 确定的时候后，需要从2，3 里面进行全排列，然后得到 1,2,3 和，1，3，2。因此得到一个算法，用一个flags 来记录这个数是否已经被用过。如果已经选到第n个字符（ level ==n) 那 阅读全文
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Clone an undirected graph. Each node in the graph contains alabeland a list of itsneighbors./** * Definition for undirected graph. * struct UndirectedGraphNode { * int label; * vector neighbors; * UndirectedGraphNode(int x) : label(x) {}; * }; */图的遍历有两种方法，一种是广度优先搜索，一种是深度优先搜索。最naive的方法就是遍... 阅读全文