Submission #1136158

#	Time	Username	Problem	Language	Result	Execution time	Memory
1136158		BuiDucManh123	Sum Zero (RMI20_sumzero)	C++20	61 / 100	636 ms	78296 KiB

sumzero

#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define taskname ""
using namespace std;

const int lg = 20;  // Logarithm base 2 of maximum n
const int MAXN = 400009;

ll n, q, ans, l, r;
ll f[lg + 1][MAXN], a[MAXN];
map<ll, ll> check;

int main() {
    if (fopen(taskname ".inp", "r")) {
        freopen(taskname ".inp", "r", stdin);
        freopen(taskname ".out", "w", stdout);
    }

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> n;

    // Initialize f array
    for (int i = 0; i < lg; i++) {
        for (int j = 0; j <= n; j++) {
            f[i][j] = -1;
        }
    }

    // Input and preprocessing
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        a[i] += a[i - 1];  // Prefix sum

        // Update the f array and map for prefix sums
        if (check.find(a[i]) == check.end() && a[i] != 0) {
            check[a[i]] = -1;
        }
        f[0][i] = max(check[a[i]], f[0][i - 1]);
        check[a[i]] = i;
    }

    // Build sparse table
    for (int i = 1; i < lg; i++) {
        for (int j = 1; j <= n; j++) {
            if (f[i - 1][j] != -1) {
                f[i][j] = f[i - 1][f[i - 1][j]];
            } else {
                f[i][j] = -1;
            }
        }
    }

    // Answer queries
    cin >> q;
    while (q--) {
        cin >> l >> r;
        ans = 0;

        for (int i = lg - 1; i >= 0; i--) {
            if (f[i][r] >= l - 1) {
                ans += (1 << i);
                r = f[i][r];
            }
        }

        cout << ans << "\n";
    }

    return 0;
}

Compilation message (stderr)

sumzero.cpp: In function 'int main()':
sumzero.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen(taskname ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sumzero.cpp:22:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |         freopen(taskname ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 39 / 39
• Subtask 3: 0 / 39