Submission #1033730

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033730		hehebjp123	Trains (BOI24_trains)	C++14	100 / 100	354 ms	165384 KiB

Main

#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define taskname ""
using namespace std;
const int mod=1e9+7;
const int block=316;
ll n,i,a[100009],d[100009],x[100009],f[350][350],ans[100009],res,j,add[350][100009];
int main() {
    if (fopen(taskname".inp","r")) {
        freopen(taskname".inp","r",stdin);
        freopen(taskname".out","w",stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n;
    for(i=1;i<=n;i++){
        cin>>d[i]>>x[i];
    }ans[1]=1;
    for(i=1;i<=n;i++){
        for(j=1;j<block;j++){
            f[j][i%j]+=add[j][i];
            f[j][i%j]%=mod;
            f[j][i%j]=(f[j][i%j]+mod)%mod;
            ans[i]+=f[j][i%j];
            ans[i]%=mod;
        }
        if(d[i]>=block){
            if(d[i]>0){
                for(j=i+d[i];j<=min(n,i+d[i]*x[i]);j+=d[i]){
                    ans[j]+=ans[i];
                    ans[j]%=mod;
                }
            }
        }else{
            if(d[i]>0){
                f[d[i]][i%d[i]]+=ans[i];
                f[d[i]][i%d[i]]%=mod;
                  if(i+d[i]*(x[i]+1)<=n){
                add[d[i]][i+d[i]*(x[i]+1)]-=ans[i];
                add[d[i]][i+d[i]*(x[i]+1)]%=mod;
                }
            }
        }
    }for(i=1;i<=n;i++) res+=ans[i],res%=mod;;
    cout<<(res+mod)%mod;
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:16:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |         freopen(taskname".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:17:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |         freopen(taskname".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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