Submission #1093388

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093388		Tymond	Trains (BOI24_trains)	C++17	100 / 100	151 ms	9892 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
 
struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
 
    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

struct Info{
    ll ind, blokSz, blokMod, val;
    Info(ll nind, ll nb, ll nm, ll nv){
        ind = nind;
        blokSz = nb;
        blokMod = nm;
        val = nv;
    }
};

const int MAXN = 1e5 + 7;
const int B = 300;
ll d[MAXN];
ll x[MAXN];
ll dp[MAXN];
int n;
ll dod[B + 7][B + 7];
const int MOD = 1e9 + 7;
vector<Info> usu[MAXN];

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

    cin >> n;
    for(int i = 1; i <= n; i++){
        cin >> d[i] >> x[i];
    }

    dp[1] = 1LL;
    for(int i = 1; i <= n; i++){
        for(auto ele : usu[i]){
            dod[ele.blokSz][ele.blokMod] -= ele.val;
            dod[ele.blokSz][ele.blokMod] += MOD;
            dod[ele.blokSz][ele.blokMod] %= MOD;
        }

        for(int j = 1; j < B; j++){
            dp[i] += dod[j][i % j];
            dp[i] %= MOD;
        }

        if(dp[i] == 0LL || d[i] == 0){
            continue;
        }

        if(d[i] >= B){
            for(int j = 1; j <= x[i]; j++){
                if(i + j * d[i] > n){
                    break;
                }
                dp[i + j * d[i]] += dp[i];
                dp[i + j * d[i]] %= MOD;
            }
            continue;
        }

        dp[i] %= MOD;
        dod[d[i]][i % d[i]] += dp[i];
        dod[d[i]][i % d[i]] %= MOD;
        if((ll)i + (ll)d[i] * x[i] + 1 <= n){
            usu[(ll)i + (ll)d[i] * x[i] + 1].pb(Info(i + d[i] * x[i] + 1, d[i], i % d[i], dp[i]));
        }
    }

    ll ans = 0LL;
    for(int i = 1; i <= n; i++){
        //cout << dp[i] << ' ';
        ans += dp[i];
        ans %= MOD;
    }
    //cout << '\n';

    cout << ans << '\n';

    return 0;
}

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