Submission #991342

#	Time	Username	Problem	Language	Result	Execution time	Memory
991342		Andrey	Trains (BOI24_trains)	C++14	100 / 100	118 ms	317804 KiB

Main

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

long long bruh[100001][400];
const long long MOD = 1e9+7;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    long long n,a,b;
    cin >> n;
    vector<pair<long long,long long>> haha(n+1);
    for(long long i = 0; i < n; i++) {
        cin >> a >> b;
        haha[i] = {a,b};
    }
    reverse(haha.begin(),haha.end());
    vector<long long> dp(n+1,1);
    dp[0] = 0;
    for(long long i = 0; i < 400; i++) {
        bruh[0][i] = 0;
    }
    for(long long i = 1; i <= n; i++) {
        a = haha[i].first;
        b = haha[i].second;
        if(a*a <= n) {
            if(i > a) {
                dp[i]+=bruh[i-a][a];
                dp[i]%=MOD;
            }
            if(i > a*(b+1)) {
                dp[i]-=bruh[i-a*(b+1)][a];
                dp[i]+=MOD;
                dp[i]%=MOD;
            }
        }
        else {
            for(long long j = i-a; j >= max(0LL,i-a*b); j-=a) {
                dp[i]+=dp[j];
                dp[i]%=MOD;
            }
        }
        for(long long j = 1; j*j <= n; j++) {
            if(j <= i) {
                bruh[i][j] = (bruh[i-j][j]+dp[i])%MOD;
            }
            else {
                bruh[i][j] = dp[i];
            }
        }
    }
    cout << dp[n];
    return 0;
}

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