Submission #1118380

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118380		somefolk	Sum Zero (RMI20_sumzero)	C++17	61 / 100	1046 ms	19672 KiB

sumzero

#include <iostream>
#include <vector>
#include <unordered_map>
using namespace std;

const int N = 4*1e5+5;
const int k = 600; // aprox. sqrt(n)

int n, q, s = 0, curr;
vector<int> a(N), idx(N), valid(N);
unordered_map<int, int> mp;


void solve(){
    cin >> n;
    for(int i = 0; i < n; i++){
        cin >> a[i];
    }

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

    mp[0] = n;
    for(int i = n-1; i >= 0; i--){
        s += a[i];
        if(mp.count(s)) idx[i] = mp[s];
        mp[s] = i;
    }
    mp.clear();

    curr = n+1;
    for(int i = n-1; i >= 0; i--){
        if(idx[i] > -1){
            curr = min(curr, idx[i]);
        }
        idx[i] = curr;
    }

    for(int i = 0; i < n; i++){
        curr = i;
        for(int j = 0; j < k && curr <= n; j++){
            curr = idx[curr];
        }
        valid[i] = curr;
    }

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

        curr = l-1;
        int sol = 0;
        while(valid[curr] <= r){
            sol += k;
            curr = valid[curr];
        }
        while(idx[curr] <= r){
            sol++;
            curr = idx[curr];
        }

        cout << sol << "\n";
    }
}

int32_t main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    solve();
    return 0;
}

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