#1. Two Sum
Given an array of integers, return indices of the two numbers such that they add up to a specific target.
You may assume that each input would have exactly one solution.
Example:
Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + nums[1] = 2 + 7 = 9, return [0, 1].
题解：暴力求解，时间复杂度O(n2)
class Solution { public: vector<int> twoSum(vector<int>& nums, int target) { vector<int> ret; for(int i=0;i<nums.size();i++) { for(int j=i+1;j<nums.size();j++) { if(nums[i]+nums[j]==target) { ret.push_back(i); ret.push_back(j); break; } } } return ret; } };
原文：http://www.cnblogs.com/fengxw/p/6082938.html