Subarray Sums II

#include <bits/stdc++.h>

using namespace std;

#define debug(...) Debug(#__VA_ARGS__, __VA_ARGS__);
template <typename... Args>
void Debug(const char* names, Args&&... args) {
   std::cerr << names << " = ";
   ((std::cerr << args << ", "), ...) << "\b\b " << std::endl;
}
#define ll long long
#define ull unsigned long long
#define vi vector<int>

int main() {
    int n;
    ll x;
    cin >> n >> x;

    vector<ll> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];

    // Prefix sum and hash map to store counts
    unordered_map<ll, ull> prefix_count;
    ll prefix_sum = 0;
    ull count = 0;

    // Initialize prefix count for 0
    prefix_count[0] = 1;

    for (int i = 0; i < n; i++) {
        prefix_sum += a[i];

        // Check if a subarray with sum x exists
        if (prefix_count.find(prefix_sum - x) != prefix_count.end()) {
            count += prefix_count[prefix_sum - x];
        }

        // Update prefix sum count
        prefix_count[prefix_sum]++;
    }

    cout << count << endl;

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: TIME LIMIT EXCEEDED