sub arr of given sum

#include <bits/stdc++.h>

using namespace std;

pair<int, int> subArrOfGivenSum(const vector<int> &nums, int target) {
    unordered_map<int, int> indexOf;
    indexOf[0] = -1;
    int prefSum = 0;
    for (int i = 0; i < (int)nums.size(); i++) {
        prefSum += nums[i];
        int diff = prefSum - target;
        if (indexOf.count(diff)) {
            return make_pair(indexOf[diff] + 1, i);
        }
        indexOf[prefSum] = i;
    }
    return make_pair(-1, -1);
}

int main() {
    vector<int> nums = {1, 1, 5, 2, 1, 3, 10, 2, 1};
    pair<int, int> ans = subArrOfGivenSum(nums, 21);
    cout << ans.first << ' ' << ans.second << endl;
    unordered_map<int, int> mp;
    return 0;
}