Leetcode 1 Two Sum STL

class Solution {
public:
vector<int> twoSum(vector<int>& nums, int target) {
vector<int> ans;
map<int,int> m;
for(int i = 0; i < nums.size(); ++i){
m[nums[i]] =  i;
}
for(int i = 0; i < nums.size(); ++i){
if(m.find(target - nums[i]) != m.end() && m[target - nums[i]]!= i){
ans.push_back(i);
ans.push_back(m[target - nums[i]]);
break;
}
}
return ans;
}
};