摘要：
http://oj.leetcode.com/problems/3sum-closest/Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution. For example, given array S = {-1 2 1 ... 阅读全文
摘要：
http://oj.leetcode.com/problems/3sum/Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements in a triplet (a,b,c) must be in non-descending order. (ie, a ≤ b ≤ c)The solution set must not 阅读全文
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http://oj.leetcode.com/problems/longest-common-prefix/Write a function to find the longest common prefix string amongst an array of strings.思路：没什么技巧，第一行第一个字符拿出来和其它所有行的第一个字符比，然后第二个，第三个。如果碰到不相等或某行结束就中断。 1 class Solution { 2 public: 3 string longestCommonPrefix(vector &strs) { 4 if (0 == st... 阅读全文
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http://oj.leetcode.com/problems/roman-to-integer/Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.思路：根据个十百千位分别作为一个状态机处理就可以了。 1 class Solution { 2 public: 3 int romanToInt(string s) { 4 int val = 0, mul = 0; 5 char one, five... 阅读全文
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http://oj.leetcode.com/problems/integer-to-roman/Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999.思路：先google一下罗马数字表示法。然后查表搞定。 1 static char* roman_table[4][9] = {{"I", "II", "III", "IV", "V", & 阅读全文
摘要：
http://oj.leetcode.com/problems/container-with-most-water/Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a 阅读全文
摘要：
http://oj.leetcode.com/problems/regular-expression-matching/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 string (not par 阅读全文