Submission #1005636

#	Time	Username	Problem	Language	Result	Execution time	Memory
1005636		TrinhKhanhDung	Trains (BOI24_trains)	C++14	100 / 100	77 ms	253176 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18
#define INF (ll)1e9
#define MOD (ll)(1e9 + 7)
#define int ll

using namespace std;

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 T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int MAX = 1e5 + 10;

int N;
int d[MAX], t[MAX];

void input(){
    cin >> N;
    for(int i=1; i<=N; i++){
        cin >> d[i] >> t[i];
    }
}

namespace subtask2{
    int f[MAX];

    void solve(){
        f[1] = 1;
        for(int i=1; i<=N; i++) if(f[i] && d[i]){
            for(int j=1; j<=t[i]; j++){
                if(i + 1LL * d[i] * j > N) break;
                add(f[i + d[i] * j], f[i]);
            }
        }

        int ans = 0;
        for(int i=1; i<=N; i++){
            add(ans, f[i]);
        }
        cout << ans << '\n';
    }
}

namespace subtask3{
    bool check(){
        for(int i=1; i<=N; i++){
            if(d[i] != 1) return false;
        }
        return true;
    }

    int f[MAX];

    void solve(){
        f[1] = 1;
        for(int i=1; i<=N; i++){
            add(f[i], f[i - 1]);
            int p = min(1LL * N, i + 1LL * d[i] * t[i]);
            add(f[i + 1], 1);
            sub(f[p + 1], 1);
        }

        int ans = 0;
        for(int i=1; i<=N; i++){
            add(ans, f[i]);
        }
        cout << ans << '\n';
    }
}

namespace subtask5{
    const int S = sqrt(MAX + 10);

    int f[MAX], g[MAX][S];

    void solve(){
        for(int i=N; i>=1; i--){
            if(d[i] < S){
                if(d[i] && t[i]){
                    ll st = i + d[i];
                    ll en = i + d[i] * (t[i] + 1);
                    if(st <= N){
                        if(en <= N)
                            add(f[i], (g[st][d[i]] - g[en][d[i]] + MOD) % MOD);
                        else
                            add(f[i], g[st][d[i]]);
                    }
                }
            }
            else if(d[i]){
                for(int j=1; j<=t[i] && i + 1LL * j * d[i] <= N; j++){
                    add(f[i], f[i + 1LL * j * d[i]]);
                }
            }
            f[i]++;

            for(int j=1; j<S; j++){
                g[i][j] = f[i];
                if(i + j <=N ) add(g[i][j], g[i + j][j]);
            }
//            cout << f[i] << ' ';
        }

        cout << f[1];
    }
}

signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
//    freopen("netw.inp", "r", stdin);
//    freopen("netw.out", "w", stdout);

    input();

    return subtask5::solve(), 0;

    return 0;
}

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