Submission #770449

#	Time	Username	Problem	Language	Result	Execution time	Memory
770449		dxz05	Sum Zero (RMI20_sumzero)	C++17	61 / 100	307 ms	26012 KiB

sumzero

#pragma GCC optimize("Ofast,O3,unroll-loops")
#pragma GCC target("avx2")

#include <bits/stdc++.h>

using namespace std;

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair
//#define endl '\n'

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

typedef long long ll;
const int MOD = 1e9 + 7;
const int N = 4e5 + 2;

const int K = 16; // base
const int L = 5;  // K^L >= N

int a[N];
int p[N];
int go[N][L];

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

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

    unordered_map<ll, int> mp;
    mp[0] = n + 1;

    ll sum = 0;
    for (int i = n; i >= 1; i--){
        sum += a[i];
        if (mp.find(sum) != mp.end()){
            p[i] = mp[sum];
        } else {
            p[i] = -1;
        }
        mp[sum] = i;
    }

    int where = -1;
    for (int i = n; i >= 1; i--){
        if (p[i] != -1){
            if (where == -1){
                where = p[i];
            } else {
                where = min(where, p[i]);
            }
        }
        go[i][0] = where;
    }
    go[n + 1][0] = -1;

    for (int j = 1; j < L; j++){
        for (int i = 1; i <= n + 1; i++){
            int v = i;
            for (int t = 0; t < K && v != -1; t++){
                v = go[v][j - 1];
            }

            go[i][j] = v;
        }
    }

    vector<int> pw(L);
    pw[0] = 1;
    for (int i = 1; i < L; i++) pw[i] = pw[i - 1] * K;

    int q;
    cin >> q;

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

        int ans = 0;
        int v = l;
        for (int i = L - 1; i >= 0; i--){
            while (go[v][i] != -1 && go[v][i] <= r){
                v = go[v][i];
                ans += pw[i];
            }
        }

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

}

int main(){
    clock_t startTime = clock();
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int test_cases = 1;
    //cin >> test_cases;

    for (int test = 1; test <= test_cases; test++){
        //cout << (solve() ? "YES" : "NO") << endl;
        solve();
    }

#ifdef LOCAL
    cerr << "Time: " << int((double) (clock() - startTime) / CLOCKS_PER_SEC * 1000) << " ms" << endl;
#endif

    return 0;
}

Compilation message (stderr)

sumzero.cpp: In function 'int main()':
sumzero.cpp:99:13: warning: unused variable 'startTime' [-Wunused-variable]
   99 |     clock_t startTime = clock();
      |             ^~~~~~~~~

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