Submission #1033561

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033561		vjudge1	Trains (BOI24_trains)	C++14	100 / 100	154 ms	9556 KiB

Main

#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define name "aaaaaa"
using ll = long long;
using pii = pair<ll, ll>;
using ld = long double;

void file(){
    ios_base::sync_with_stdio(0); cin.tie(0);
    if(fopen(name".inp", "r")) {
        freopen(name".inp", "r", stdin);
        freopen(name".out", "w", stdout);
    }
}

const ll maxn = 1e5 + 5;
const ll maxs = 320;
const ll mod = 1e9 + 7;

ll d[maxn], x[maxn];

ll dp[maxn];

ll sus[maxs][maxs];

vector<pair<pii, ll>> v[maxn];

void solve (){
    ll n; cin >> n;
    for(ll i = 1; i <= n; i++){
        cin >> d[i] >> x[i];
    }
    dp[1] = 1;
    for(ll i = 1; i <= n; i++){
        for(auto j : v[i]){
            ll p1 = j.first.first, p2 = j.first.second, p3 = j.second;
            sus[p1][p2] += p3;
            if(sus[p1][p2] < 0){
                sus[p1][p2] += mod;
            }
        }
        for(ll j = 1; j < maxs; j++){
            dp[i] += sus[j][i % j];
            dp[i] %= mod;
        }
        if(d[i] >= maxs){
            for(ll j = 1; j <= x[i]; j++){
                if(i + d[i] * j > n) break;
                dp[i + d[i] * j] += dp[i];
                dp[i + d[i] * j] %= mod;
            }
        }else if(d[i] != 0){
            sus[d[i]][i % d[i]] += dp[i];
            sus[d[i]][i % d[i]] %= mod;
            ll pos = i + (x[i] + 1) * d[i];
            if(pos <= n){
                v[pos].push_back({{d[i], i % d[i]}, -dp[i]});
            }
        }
    }
    ll ans = 0;
    for(ll i = 1; i <= n; i++){
        ans += dp[i];
    }
    cout << ans % mod;
}

int main(){
    file();
    ll t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

Main.cpp: In function 'void file()':
Main.cpp:12:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |         freopen(name".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:13:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |         freopen(name".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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