Submission #1303359

#	Time	Username	Problem	Language	Result	Execution time	Memory
1303359		khanhgng	Trains (BOI24_trains)	C++20	16 / 100	157 ms	5716 KiB

Main

#include<bits/stdc++.h>
#define ll long long
#define int long long
#define ld long double
#define pb push_back
#define pii pair<int, int>
#define fi first
#define se second
#define bit(i, x) ((x >> i) & 1)
#define SZ(x) ((int)(x.size()))
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define task "test"

using namespace std;

mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll Rand(ll l, ll r) { assert(l <= r); return uniform_int_distribution<ll>(l, r)(rd); }

const int MAXn = 2e5+10;
const int MX = 1e5+10;
const ll INF = (long long)(1e18);
const int MOD = 1e9+7;
const int BASE = 3137;
const int BL = 350;

int n,d[MAXn],x[MAXn],dp[MAXn];
int f[BL+5][BL+5];
vector<int>vec[MAXn];

void solution() {
    cin>>n;
    FOR(i,1,n){
        cin>>d[i]>>x[i];
    }
    dp[1]=1;
    FOR(i,1,n){
        ///
        for(int j:vec[i]){
            f[d[j]][(j+d[j])%d[j]]-=dp[j];
            f[d[j]][(j+d[j])%d[j]]+=MOD;
            f[d[j]][(j+d[j])%d[j]]%=MOD;
        }
        if(d[i]>=BL){
            FOR(j,1,x[i]){
                dp[j*d[i]+i]+=dp[i];
                dp[j*d[i]+i]%=MOD;;
            }
        }
        else {
            FOR(j,1,BL){
                dp[i]+=f[j][i%j];
                dp[i]%=MOD;
            }
            if(d[i]==0||x[i]==0)continue;
            f[d[i]][(i+d[i])%d[i]]+=dp[i];
            f[d[i]][(i+d[i])%d[i]]%=MOD;
            if(d[i]*x[i]+i+1<=n)vec[d[i]*x[i]+i+1].pb(i);

        }
    }
    int rs=0;
    FOR(i,1,n){
        rs+=dp[i];
        rs%=MOD;
    }
    cout << rs;
}




int32_t main() {
    if (fopen(task".inp", "r")){freopen(task".inp", "r", stdin);freopen(task".out", "w", stdout);}
    ios::sync_with_stdio(0); cin.tie(0);
    int ntest = 1; ///  cin >> ntest;
    while (ntest--) solution();
    cerr << "\n" << 1.0 * clock() / CLOCKS_PER_SEC << "s ";
}

Compilation message (stderr)

Main.cpp: In function 'int32_t main()':
Main.cpp:74:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |     if (fopen(task".inp", "r")){freopen(task".inp", "r", stdin);freopen(task".out", "w", stdout);}
      |                                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:74:72: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |     if (fopen(task".inp", "r")){freopen(task".inp", "r", stdin);freopen(task".out", "w", stdout);}
      |                                                                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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