Submission #1180932

#	Time	Username	Problem	Language	Result	Execution time	Memory
1180932		steveonalex	Trains (BOI24_trains)	C++20	100 / 100	139 ms	130868 KiB

Main

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ull mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }
const int MOD = 1e9 + 7;
struct Modular{
    int x;
    Modular(int _x = 0){
        x = _x % MOD;
        if (x < 0) x += MOD;
    }
    Modular& operator += (Modular y){
        x += y.x;
        if (x >= MOD) x -= MOD;
        return *this;
    }
    Modular operator + (Modular y) {
        Modular tmp = *this;
        return tmp += y;
    }
 
    Modular& operator -= (Modular y){
        x -= y.x;
        if (x < 0) x += MOD;
        return *this;
    }
    Modular operator - (Modular y) {
        Modular tmp = *this;
        return tmp -= y;
    }
 
    // use at your own risk
    bool operator == (Modular y){
        return x == y.x;
    }
    bool operator != (Modular y){
        return x != y.x;
    }
};
ostream& operator << (ostream& out, Modular x){
    out << x.x;
    return out;
}
 
 
const int N = 1e5 + 69, BLOCK = 330;
 
Modular wow[N][BLOCK];
 
void solve(){
    int n; cin >> n;
    vector<int> d(n+1), x(n+1);
    for(int i = 1; i <= n; ++i) cin >> d[i] >> x[i];
 
    vector<Modular> dp(n+1);
    dp[1] = 1;
    Modular ans = 0;
    for(int i = 1; i <= n; ++i){
        for(int j = 1; j < BLOCK; ++j){
            if (i >= j) wow[i][j] += wow[i-j][j];
            dp[i] += wow[i][j];
        }
        ans += dp[i];
        if (d[i] == 0) continue;
        if (d[i] >= BLOCK){
            for(int j = 1; j <= x[i]; ++j){
                int p = i + j * d[i];
                if (p > n) break;
                dp[p] += dp[i];
            }
        }
        else{
            if (i + d[i] > n) continue;
            int l = i + d[i];
            int r = i + min((n - i) / d[i], x[i]) * d[i];
            wow[l][d[i]] += dp[i];
 
            if (r + d[i] <= n)
                wow[r+d[i]][d[i]] -= dp[i];
        }
    }
 
    cout << ans << "\n";
}
 
int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
 
    solve();
 
    return 0;
}

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