Submission #772695

#	Time	Username	Problem	Language	Result	Execution time	Memory
772695		cnastea	Fountain (eJOI20_fountain)	C++14	60 / 100	1558 ms	34876 KiB

fountain

#include <bits/stdc++.h>
using namespace std;
#define int long long
int u[100000][20];
int s[100000][20];
vector<int> c(100000);

int j(int v, int x){
    bool b[20];
    for(int i = 0; i < 20; i++){
        if((x >> i) & 1) b[i] = 1;
        else b[i] = 0;
    }
    int r = v;
    for(int i = 0; i < 20; i++){
        if(b[i]){
            r = u[r][i];
        }
    }
    return r;
}

int f(int v, int x){
    bool b[20];
    for(int i = 0; i < 20; i++){
        if((x >> i) & 1) b[i] = 1;
        else b[i] = 0;
    }
    int p = 0;
    int r = v;
    for(int i = 0; i < 20; i++){
        if (r == -1) break;
        if(b[i]){
            p += s[r][i];
            r = u[r][i];
        }
    }
    return p;
}

int32_t main()
{
    int n, q;
    cin >> n >> q;
    vector<int> d(n);
    for(int i = 0; i < n; i++){
        cin >> d[i] >> c[i];
    }
    for(int i = 0; i < n; i++){
        for(int k = 0; k < 20; k++) u[i][k] = -1;
    }
    for(int i = 0; i < n; i++){
        for(int k = i+1; k < n; k++){
            if(d[k] > d[i]){
                u[i][0] = k;
                break;
            }
        }
    }
    for(int k = 1; k < 20; k++){
        for(int i = 0; i < n; i++){
            if(u[i][k-1] != -1) u[i][k] = u[u[i][k-1]][k-1];
            else u[i][k] = -1;
        }
    }
    for(int i = 0; i < n; i++){
        s[i][0] = c[i];
    }
    for(int k = 1; k < 20; k++){
        for(int i = 0; i < n; i++){
            if(u[i][k-1] != -1) s[i][k] = s[i][k-1] + s[u[i][k-1]][k-1];
            else s[i][k]=s[i][k-1];
        }
    }
    for(int i = 0; i < q; i++){
        int r, v;
        cin >> r >> v;
        if(v > f(r-1, n-1)) cout << 0 << "\n";
        else{
            int a = 0, b = n;
            int m;
            while(b > a){
                m = (a+b+1)/2;
                if(f(r-1, m) < v) a = m;
                else b = m-1;
            }
            cout << j(r-1, b)+1 << "\n";
        }
    }
    
    return 0;
}

/*
2 1
1 1
1 1
2 1
*/

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 0 / 40