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, and you may not use the same element twice.
Example:
Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + nums[1] = 2 + 7 = 9, return [0, 1].
1 class Solution { 2 public: 3 vector<int> twoSum(vector<int>& nums, int target) { 4 unordered_map<int, int> hash; 5 vector<int> result; 6 for(int i = 0; i < nums.size(); i++){ 7 if(hash.find(target - nums[i]) != hash.end()){ 8 result.push_back(hash[target - nums[i]]); 9 result.push_back(i); 10 return result; 11 } 12 hash[nums[i]] = i; 13 } 14 result.push_back(-1); 15 result.push_back(-1); 16 return result; 17 } 18 };
原文：http://www.cnblogs.com/93scarlett/p/6360886.html
