摘要：
You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)Output: 7 -> 0 -> 8模拟加法，注意最后加法结束时可能有进位 阅读全文
摘要：
Given two binary strings, return their sum (also a binary string).For example,a ="11"b ="1"Return"100".这题用数组来做可能更简单，但考虑到可能面试的时候要求不能开额外的数组，就只能对string操作了。最主要的是把进位这部分写对。 1 class Solution { 2 public: 3 string addBinary(string a, string b) { 4 // Start typing your C/C++ solu 阅读全文
摘要：
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 contain duplicate triplets. For e... 阅读全文
摘要：
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 array which gives the sum of target.Note:Elements in a quadruplet (a,b,c,d) must be in non-descending order. (ie, a ≤ b ≤ c ≤ d)The solution set must not contai 阅读全文
摘要：
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 -4}, and target = 1.The sum that is closest to th 阅读全文