LeetCode 1. Sum of two numbers

Given an array of integers nums And an integer target value target, Please find... In the array And is the target value target the Two Integers , And return their array subscripts .

You can assume that each input corresponds to only one answer . however , The same element in the array cannot be repeated in the answer .

You can return the answers in any order .

class Solution {
    
public:
    vector<int> twoSum(vector<int>& nums, int target) {
    
        vector<int> re;
        unordered_map<int, int> hash;  //  Record where the number appears 
        for(int i=0; i<nums.size(); i++)
        {
    
            int other = target - nums[i];
            if(hash.count(other))
            {
    
                re = vector<int>({
    hash[other], i});
                break;
            }
            hash[nums[i]] = i;
        }
        return re;
    }
};