Submission #1308822

#	Time	Username	Problem	Language	Result	Execution time	Memory
1308822		majawieczorek	Fountain (eJOI20_fountain)	C++20	100 / 100	151 ms	46240 KiB

fountain

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define s second
#define f first

const ll N = 1e5 + 10, K = 17, MAXX = 1e9;
int n;

pair<int, ll> jump[N][K + 10];

vector <pair<ll, ll>> V;
stack <ll> stos;

ll jump_(int v, ll x) {
    ll k = K, suma = 0;
    while(suma < x && k >= 0) { 
        if(jump[v][k].second + suma < x) {suma += jump[v][k].second; v = jump[v][k].first;}
        k--;
    }

    if(suma < x) {suma += jump[v][0].second; v = jump[v][0].first;}

    if(v == n) return -1;
    return v;
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    int m; cin >> n >> m;

    for(int i = 0; i < n; i++) {
        int d, c; cin >> d >> c;
        V.push_back({d, c});
    }

    for(int i = V.size() - 1; i >= 0; i--) {
        ll a = V[i].f;
        while(!stos.empty() && V[stos.top()].f <= a) stos.pop();
        
        if(!stos.empty()) jump[i][0] = {stos.top(), V[stos.top()].s};
        else jump[i][0] = {n, MAXX};
        stos.push(i);
    }
    for(int i = 0; i <= K; i++) jump[n][i] = {n, MAXX};

    for(int j = 1; j <= K; j++) {
        for(int i = 0; i < n; i++) {
            jump[i][j] = {jump[jump[i][j - 1].f][j - 1].f, jump[i][j - 1].s + jump[jump[i][j - 1].f][j - 1].s};
            jump[i][j].s = min(MAXX, jump[i][j].s);
        }
    }

    while(m--) {
        ll r, v; cin >> r >> v;
        r--; v -= V[r].s; 
        
        cout << jump_(r, v) + 1 << '\n';
    }


    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40