Given[-3, 1, 2, -3, 4], return[0, 2]or[1, 3].

class Solution {
public:
    /**
     * @param nums: A list of integers
     * @return: A list of integers includes the index of the first number 
     *          and the index of the last number
     */
    vector<int> subarraySum(vector<int> nums){
        // write your code here
        vector<int> results;
        int size = nums.size();
        if (size == 0) {
            return results;
        }
        unordered_map<int, int> map;
        // We set the index -1 sum to be 0 to let us more convient to count.
        map.insert({0, -1});
        int sum = 0;
        for (int i = 0; i < size; i++) {
            sum += nums[i];
            if (map.find(sum) != map.end()) {
            // For example: 
            //        -3  1  2 -3 4
            // SUM: 0 -3 -2  0 -3 1
            // then we got the solution is : 0 - 2
                results.push_back(map[sum]+1);
                results.push_back(i);
                return results;
            } else {
                map[sum] = i;
            }
        }

    }
};