摘要： 题目描述： Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the arra 阅读全文

摘要： 题目描述： 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 int 阅读全文

摘要： 题目描述： 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 s 阅读全文

摘要： 题目描述： Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 解题思路： 观察罗马数字可以发现个十百千位上的数字是可以分开考虑的。 而 阅读全文

摘要： 题目描述： 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 阅读全文

摘要： 题目描述： The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed 阅读全文

摘要： 题目描述： Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example: Example: 本题要我们找的是字符 阅读全文

摘要： 题目描述： Given a string, find the length of the longest substring without repeating characters. Examples: Given "abcabcbb", the answer is "abc", which th 阅读全文

摘要： 题目描述： You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes 阅读全文

摘要： 题目描述： Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example: 本题要我们将阿拉伯数字转化为Excel工作簿中列的标题。 解题思路： 本题相 阅读全文