Submission #1207712

#	Time	Username	Problem	Language	Result	Execution time	Memory
1207712		dksnfjkfnwkfw	Trains (BOI24_trains)	C++20	24 / 100	44 ms	6736 KiB

Main

#include <bits/stdc++.h>
using namespace std;

#define sonic ios_base::sync_with_stdio(false);cin.tie(0); cout.tie(0)
#define IO(main) if(fopen(main".inp","r")){freopen(main".inp","r",stdin);freopen(main".out","w",stdout);}
#define pb push_back
#define fi first
#define se second
#define mp make_pair
#define ins insert
#define pb push_back
#define el cout << endl
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()
#define MASK(i) ((1LL)<<(i))
#define BIT(x,i) (((x)>>(i))&(1LL))
#define FOR(i, a, b) for(int (i)=(a);(i)<=(b); i++)
#define FORD(i, a, b) for(int (i)=(a);(i)>=(b); i--)


using ll = long long;
#define int ll
using ull = unsigned long long;
using ld = long double;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vii = vector<pii>;

const int N = 1e6 + 9;
const int mod = 1e9 + 7;
const ll INF = 1e18 + 7;
const int base = 31;
const int LOG = 20;
const ll MOD = 1e9 + 7;

int mul(int x, int y) {return 1LL * x * y % mod;}
int calPw(int x, int y)
{
    int ans = 1;
    while(y)
    {
        if (y&1) ans = 1LL * ans * x % mod;
        x = 1LL * x * x % mod;
        y >>= 1;
    }
    return ans;
}
int d4x[4] = {1, 0, -1, 0};
int d4y[4] = {0, 1, 0, -1};
int dx[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int dy[8] = {1, 1, 0, -1, -1, -1, 0, 1};
///Author: Le Chi Thien Luong The Vinh high school 2008
///code
template<class X, class Y>
bool minimize(X &x , Y y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}
template<class X, class Y>
bool maximize(X &x , Y y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
void add(int &x, int y){
    x+=y;
    if(x >= mod)x-=mod;
}
void Solve(){

}
int n, x[N], d[N], dp[N];
struct ST{
    int st[4 * N + 2], lz[4 * N + 2];
    void push(int id){
        if(lz[id] == 0)return;
        add(st[id * 2], lz[id]);
        add(st[id * 2 + 1], lz[id]);
        add(lz[id * 2], lz[id]);
        add(lz[id * 2 + 1], lz[id]);
        lz[id] = 0;
    }
    void update(int u, int v, int val, int id = 1, int l =1 , int r = n){
        if(v < l || r < u)return;
        if(l >= u && r <= v){
            add(st[id], val);
            add(lz[id], val);
            return ;
        }
        push(id);
        int mid = l + r >> 1;
        update(u, v, val, id * 2, l, mid);
        update(u, v, val, id * 2 + 1, mid + 1, r);
        st[id] = max(st[id * 2], st[id * 2 + 1]);
    }
    int get(int u, int v, int id = 1, int l = 1, int r = n){
        if(v < l || r < u)return -INF;
        if(l >= u && r <= v)return st[id];
        int mid = l + r >> 1;
        push(id);
        int A = get(u, v, id * 2, l, mid);
        int B = get(u, v, id * 2 + 1, mid + 1, r);
        return max(A, B);
    }
}it;
void Read(){
    cin >> n;
    FOR(i, 1, n){
        cin >> d[i] >> x[i];
    }
    if(n <= 1000){
        dp[1] = 1;
    FOR(i, 1, n){
        if(dp[i] > 0)
        for(int j = i + d[i]; j <= min(n, i + d[i] * x[i]); j += d[i]){
            if(i >= j)break;
            add(dp[j], dp[i]);
        }
    }
    int Ans = 0;
    FOR(i, 1, n)add(Ans, dp[i]);
    cout << Ans;return;
    }
    it.update(1, 1, 1);
    FOR(i, 1, n){
        dp[i] = it.get(i, i);
        int mx = min(n, i + d[i] * x[i]);
        if(i + 1 <= n)
        {
//            cout << i + 1 << " " << mx << " " << dp[i] << " " << it.get(4, 4)<< endl;
            if(i + 1 > mx)continue;
            it.update(i + 1, mx, dp[i]);
           /// cout << i + 1 << " " << mx << " " << dp[i] << " " << it.get(4, 4)<< endl;
        }
    }
    int ans = 0;
    FOR(i, 1, n)add(ans, it.get(i, i));
    cout << ans;
}



signed main()
{
    sonic;

    int TEST = 1;
   // cin >> TEST;
    while(TEST--)
    {

        Read();
        Solve();
    }
}

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