제출 #1353249

#제출 시각아이디문제언어결과실행 시간메모리
1353249bakhtiyarnSum Zero (RMI20_sumzero)C++20
61 / 100
236 ms42016 KiB
// GPT fastered the map
#include <bits/stdc++.h>
using namespace std;

const int N = 4e5+5;
int up[N][20];
int idx[N];

void solve(){
    int n; cin >> n;

    for(int i=0; i<=n; i++) idx[i] = 1e9;

    vector<long long> pre(n+1);
    for(int i=1;i<=n;i++){
        int x; cin >> x;
        pre[i] = pre[i-1] + x;
    }

    // 🔥 coordinate compression
    vector<long long> vals = pre;
    sort(vals.begin(), vals.end());
    vals.erase(unique(vals.begin(), vals.end()), vals.end());

    auto get_id = [&](long long x){
        return lower_bound(vals.begin(), vals.end(), x) - vals.begin();
    };

    vector<int> last(vals.size(), -1);

    for(int i=0; i<=n; i++) {
        int id = get_id(pre[i]);

        if(last[id] != -1) up[i][0] = last[id];
        else up[i][0] = -1;

        last[id] = i;

        if(up[i][0] != -1)
            idx[up[i][0]] = min(idx[up[i][0]], i);
    }

    int mn = 1e9;
    for(int i=n; i>=0; i--){
        if(idx[i] != 1e9) mn = min(mn, idx[i]);

        if(mn == 1e9) up[i][0] = n+1;
        else up[i][0] = mn;

        for(int k=1; k<20; k++) {
            if (up[i][k-1] > n) up[i][k] = n + 1;
            else up[i][k] = up[up[i][k-1]][k-1];
        }
    }

    int q; cin >> q;
    while(q--){
        int l, r; cin >> l >> r; l--;
        int ans = 0;
        for(int b=19; b>=0; b--){
            if(up[l][b] > r) continue;
            ans += 1<<b;
            l = up[l][b];
        }
        cout << ans << '\n';
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    solve();
}
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