Submission #1033804

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033804		_shr104	Trains (BOI24_trains)	C++14	0 / 100	2048 ms	1852 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef int ll;
typedef long double ld;
#define pb push_back
#define pf push_front
#define fi first
#define se second
const ll mod = 1e9+7, mxn = 1e5+7, block = 320;
ll d[mxn], x[mxn], n;
long long dp[mxn];
signed main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    // freopen("test.inp","r",stdin); freopen("test.out","w",stdout); freopen("test.err","w",stderr);
    ll n; cin >> n; dp[1] = 1;
    vector<pair<ll,pair<ll,ll>>> v;
    for (ll i = 1; i <= n; i++) 
    {
        cin >> d[i] >> x[i];
        for (pair<ll,pair<ll,ll>> j : v) if ((i-j.fi)%j.se.fi == 0 && (i-j.fi)/j.se.fi <= j.se.se)
        {
            dp[i] += dp[j.fi]; 
            if (dp[i] >= mod) dp[i] -= mod;
        }
        if (!d[i]) continue;
        x[i] = (n-(long long)i*d[i])/d[i];
        if (x[i] <= block)
        {
            if (i+d[i] > n) continue;
            for (ll j = i+d[i]; j <= min(n, i+x[i]*d[i]); j += d[i]) 
            {
                dp[j] += dp[i];
                if (dp[j] >= mod) dp[j] -= mod;
            }
        }
        else v.pb({i,{d[i],x[i]}}); 
    }
    long long ans = 0;
    for (ll i = 1; i <= n; i++) {ans += dp[i]; if (ans >= mod) {ans -= mod;}}
    cout << ans;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 13
• Subtask 3: 0 / 16
• Subtask 4: 0 / 34
• Subtask 5: 0 / 29