Approach#3 hash table

LeetCode_1. Two Sum_1.cpp

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        map<int, int> hashTable;
        vector<int> outVec;
        int i;
        for(i=0; i<nums.size(); i++){
            map<int, int>::iterator it = hashTable.find(target-nums[i]);
            if(it != hashTable.end()){
                outVec.push_back(it->second);
                outVec.push_back(i);
                return outVec;
            }
            hashTable.insert(pair<int, int>(nums[i],i));
        }
    }
};