Submission #1206858

#	Time	Username	Problem	Language	Result	Execution time	Memory
1206858		hieptk	Sum Zero (RMI20_sumzero)	C++20	0 / 100	18 ms	31808 KiB

sumzero

#include <iostream>
#include <vector>
#include <cmath>
#include <numeric>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <cstring>
#include <unordered_map>
#include <iomanip>
#include <queue>
#include <map>
#include <sstream>
#include <stack>
#include <bitset>

using ll = long long;
using ld = long double;
 
using namespace std;

constexpr int nm = 400002;

int n, m;
ll a[nm], s[nm];
int previ[nm][20];

int getPrev(int i, int j) {
    for (int u = 0; u < 20 && j && i >= 0; ++u) {
        if ((j >> u) & 1) {
            i = previ[i][u];
            j &= ~(1 << u);
        }
    }
    return i;
}

int f(int u, int v) {
    int l = 1, r = v - u + 1;
    while (l <= r) {
        int mid = (l + r) / 2;
        if (getPrev(v, mid) >= u - 1) {
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }
    return l - 1;
}

int main() {
    #ifdef LOCAL
    freopen("input.txt", "r", stdin);
    #endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    unordered_map<ll, int> seen;
    seen[0] = 0;
    memset(previ, -1, sizeof(previ));
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        s[i] = s[i - 1] + a[i];
        previ[i][0] = previ[i - 1][0];
        if (seen.count(s[i])) {
            previ[i][0] = max(seen[s[i]], previ[i][0]);
        }
        seen[s[i]] = i;
    }

    for (int j = 1; j < 20; ++j) {
        for (int i = (1 << j); i <= n; ++i) {
            int u = previ[i][j - 1];
            if (u >= 0) previ[i][j] = previ[u][j - 1];
        }
    }

    cin >> m;
    int l, r;
    for (int i = 0; i < m; ++i) {
        cin >> l >> r;
        cout << f(l, r) << "\n";
    }
}

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