题目: The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ... 1 is read off as "one 1" or 11.11 is read off as "two 1s" or 21.21 is read off as "one 2, then one 1" or 1211. Given…

题目: Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 代码: class Solution { public: string intToRoman(int num) { ) return NULL; ; std::string symbol_ori[size] = {"M","D","C&…

题意: 给出老虎的起始点.方向和驴的起始点.方向.. 规定老虎和驴都不会走自己走过的方格,并且当没路走的时候,驴会右转,老虎会左转.. 当转了一次还没路走就会停下来.. 问他们有没有可能在某一格相遇.. 思路: 模拟,深搜.. 用类似时间戳的东西给方格标记上,表示某一秒正好走到该方格.. 最后遍历一下驴在某一格方格标记时间是否和老虎在该格标记的时间一样,一样代表正好做过这里了.. 还有一种情况就是老虎或驴一直停在那里,那就算不相等,也是可以的.. Tips: 我一直忘了老虎或驴停下来的情况,这样…

题目: Given an array of integers, every element appears three times except for one. Find that single one. Note:Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory? 代码: class Solution { public: int s…

一道字符串匹配的题目,仅仅借此题练习一下KMP 因为这道题目就是要求用从头开始的n个字符串去匹配原来的字符串,很明显与KMP中求next的过程很相似,所以只要把能够从头开始匹配一定个数的字符串的个数加起来就OK了(再此结果上还应该加上字符串的长度,因为每个从头开始的字符串本身也可以去匹配自己的),即将next中值不为-1和0的个数统计出来即可. 用GCC编译的,时间用了46MS. #include <stdio.h> #include <string.h> #define MAXL…

题目: Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order. You may assume no duplicates in the array. Here are few examples.[1,3,5,6], 5 → 2[1,3,5,6],…

题目: Given an unsorted integer array, find the first missing positive integer. For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2. Your algorithm should run in O(n) time and uses constant space. 代码: class Solution { public: int firstMissingPos…

题目: Sort a linked list using insertion sort. 代码: /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* insertionSortList(ListNode…

题目: Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array. Note:You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements i…

题目: Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2], [5,8,4,5] ] 代码: /** * Defini…