Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each number in C may only be used once in the combination. Note: All numbers (including target) will be posi…

Write a program to solve a Sudoku puzzle by filling the empty cells. Empty cells are indicated by the character '.'. You may assume that there will be only one unique solution. A sudoku puzzle... ...and its solution numbers marked in red. 题意分析: 本题是要解…

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], 2 →…

算法和数据结构知识点图 首先,了解算法和数据结构有哪些知识点,在后面的学习中有 大局观,对学习和刷题十分有帮助. 下面是我花了一天时间花的算法和数据结构的知识结构,大家可以看看. 后面是为大家 精心挑选的LeetCode题单,并根据题目知识点的类型分好了类别,大家可以根据每个知识点,进行有针对性的刷题. 数据结构 数组&双指针 LeetCode 1. 两数之和 LeetCode 4. 寻找两个正序数组的中位数 LeetCode 15. 三数之和 LeetCode 75. 颜色分类 LeetCod…

13.Roman to Integer Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, two is written as II in Roman numeral, just two one's added together. Twelve is writ…

13. 罗马数字转整数 13. Roman to Integer 题目描述 罗马数字包含以下七种字符: I,V,X,L,C,D 和 M. 字符        数值  I           1  V           5  X           10  L           50  C           100  D           500  M           1000 例如,罗马数字 2 写做 II,即为两个并列的 1.12 写做 XII,即为 X + II.27 写做 XX…

[Q10] Given an input string (s) and a pattern (p), implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of the preceding element. The matching should cover the entire input str…

[Q13] Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, two is written as II in Roman numeral, just two one's added together. Twelve is written as, XII, w…

Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 题解:转换的方法:从左往右扫描罗马字符,如果当前的字符对应的数字比上一个数字小,就直接加上这个数字:否则加上这个数字并且减去上一个数字的两倍,然后更新上一个数字.利用一个HashMap存放罗马字符和数字的对应. 罗马数字和阿拉伯数字的对应表格参见http://www.cnblogs.…

Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 题解:基本的罗马字符和数字对应如下表所示: 罗马字符 数字 I 1 V 5 X 10 L 50 C 100 D 500 M 1000 每隔一个字符又可以与相邻的两个字符组成一个新的数,例如I可以和V和X组成IV和IX,这样又可以生成6个数字,如下表: 罗马字符 数字 IV 4 IX…