Submission #1353246

#TimeUsernameProblemLanguageResultExecution timeMemory
1353246bakhtiyarnSum Zero (RMI20_sumzero)C++20
61 / 100
575 ms22636 KiB
// GPT code
#include <bits/stdc++.h>
using namespace std;

const int N = 400000 + 5;

int n;
int nxt[N];   // next jump
int to[N];    // block jump destination
int cnt[N];   // jumps inside block
int block_id[N];

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> n;

    // compute prefix and nxt[]
    unordered_map<long long,int> last;
    last.reserve(n);
    last.max_load_factor(0.7);

    long long pre = 0;
    last[0] = 0;

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

    vector<int> idx(n+1, 1e9);

    for(int i=1;i<=n;i++){
        pre += a[i];
        if(last.count(pre)){
            int j = last[pre];
            idx[j] = min(idx[j], i);
        }
        last[pre] = i;
    }

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

    // build sqrt blocks
    int B = sqrt(n) + 1;
    for(int i=0;i<=n;i++){
        block_id[i] = i / B;
    }

    for(int i=n;i>=0;i--){
        if(nxt[i] > n){
            to[i] = n+1;
            cnt[i] = 0;
        }
        else if(block_id[i] == block_id[nxt[i]]){
            to[i] = to[nxt[i]];
            cnt[i] = cnt[nxt[i]] + 1;
        }
        else{
            to[i] = nxt[i];
            cnt[i] = 1;
        }
    }

    int q; cin >> q;
    while(q--){
        int l, r;
        cin >> l >> r;
        l--;

        int ans = 0;

        while(l <= r){
            if(to[l] <= r){
                ans += cnt[l];
                l = to[l];
            }
            else{
                if(nxt[l] <= r){
                    ans++;
                    l = nxt[l];
                } else break;
            }
        }

        cout << ans << '\n';
    }

    return 0;
}
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