Leetcode 1. Two Sum(hash+stl)

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].

 class Solution {
 public:
     vector<int> twoSum(vector<int>& nums, int target) {
         vector<int> tm;
         int a = , b = ;
         int len = nums.size();

         multimap<int,int> hash;

         for(int i = ; i < len; i++){
             hash.insert(pair<int,int>(nums[i],i));
         }
         for(int i = ; i < len; i++){
             multimap<int,int>::iterator s;
             s=hash.find(target-nums[i]);
             if(s== hash.end()){
                 continue;
             }
             if(i != (*s).second){
                 a = i;
                 b = (*s).second;
                 break;
             }
         }
         tm.push_back(a);
         tm.push_back(b);
         return tm;
     }
 };