Submission #1044588

#	Time	Username	Problem	Language	Result	Execution time	Memory
1044588		Benmath	Trains (BOI24_trains)	C++14	100 / 100	345 ms	198796 KiB

Main

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin >> n;
    long long int dp[n + 2];
    long long int con=250;
    long long int bo[n + 2][con];
    long long int mod = 1e9 + 7;
    for(int i = 0; i <= n;i++){
        dp[i] = 0;
        for(int j = 0; j < con; j++){
            bo[i][j] = 0;
        }
    }
    for(int i = 1; i <= n; i++){
        for(int j = 1; j < con; j++){
            dp[i] = (dp[i] + bo[i][j])% mod;
        }
        if(i == 1){
            dp[i] = 1;
        }
        long long int d,x;
        cin >> d >> x;
        if(d >= con){
            long long int to = i + d;
            long long int i1 = i;
            long long int limit = i1 + d*x;
            while(to <= n){
                if(to > limit){
                    break;
                }
                dp[to] = (dp[to] + dp[i])%mod;
                to = to + d;
            }
        }else{
            bo[i][d] = (bo[i][d] + dp[i])% mod;
            long long int to = i + (x + 1) * d;
            if(to <= n){
                bo[to][d] = (bo[to][d] - dp[i] + mod)% mod;
            }
        }
        for(int j = 1; j < con; j++){
            if((i + j) <= n){
                bo[i + j][j] = (bo[i + j][j] + bo[i][j])%mod;
            }
        }
        
    }
    long long int sum = 0;
    for(int i = 1; i <= n; i++){
        sum = (sum + dp[i])% mod;
    }
    cout << sum;
}

• Subtask 1: 8 / 8
• Subtask 2: 13 / 13
• Subtask 3: 16 / 16
• Subtask 4: 34 / 34
• Subtask 5: 29 / 29