Submission #1275304

#	Time	Username	Problem	Language	Result	Execution time	Memory
1275304		diep38	Trains (BOI24_trains)	C++20	100 / 100	117 ms	9232 KiB

Main

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

#define ed "\n"
#define fi first
#define se second
#define db double
#define irs insert
#define pb push_back
#define mpa make_pair
#define pi pair<int,int>
#define MASK(i) (1LL << (i))
#define BIT(x, i) ((x>>i)&1)
#define ON(x, i) ((x)  MASK(i))
#define OFF(x, i) ((x) & ~MASK(i))
#define ALL(v) v.begin() , v.end()
#define bp(x) __builtin_popcount(x)
#define pii pair<int,pair<int,int>>
#define fl(i,a,b) for(int i=a;i>=b;--i)
#define fis(i,a,b) for(int i=a;i<=b;++i)
#define Radian(x) (x * acos(-1.0) / 180)
const double eps = 1e-9;
const int mod=1e9+7;
const int Mdem=998244353;
const int LOG=19;
const int base=31;
const int maxn=2e5+5;
const int bl = 320;
#define fast ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define gay(a) freopen(a".inp","r",stdin),freopen(a".out","w",stdout)
template <class T>
bool minimize(T &a, const T &b) {
    if(a > b) {a = b; return 1;}
    return 0;
}

template <class T>
bool maximize(T &a, const T &b) {
    if(a < b) {a = b; return 1;}
    return 0;
}
template <class T>
void compress(vector <T> &v) {
    sort(ALL(v));
    v.erase(unique(ALL(v)), (v).end());
}

void add(int &a, int b) {   a += b; if (a >= mod)   a -= mod;   }
void sub(int &a, int b) {   a -= b; if (a <  0)     a += mod;   }
struct Fenwick{
    int n;
    vector<int> tree;
    Fenwick(int _n = 0){
        n = _n;
        tree.resize(n + 1);
    }
    void update(int x, int val){
        if(val == -1) val = tree[x];
        for(; x <= n; x += x & -x) add(tree[x], val);
    }
    int get(int x){
        int res = 0;
        for(; x; x -= x & -x) add(res, tree[x]);
        return res;
    }
    int query(int l, int r){
        if(l == 0) return get(r);
        if(r == 0) return 0;
        else{
            int x = get(r); sub(x, get(l - 1));
            return x;
        }
    }
};
int n, dp[maxn], d[maxn], x[maxn];
int sum[325][maxn];
int block = 320;
vector<int> Del[maxn];
signed main(){
    fast;
    cin >> n;
//    Fenwick f = Fenwick(n);
    fis(i, 1, n) cin >> d[i] >> x[i];
    dp[1] = 1;
    fis(i, 1, n){
        for(int j : Del[i]) sub(sum[d[j]][j % d[j]], dp[j]);
        fis(j, 1, block) add(dp[i], sum[j][i % j]);
        if(d[i] > block){
            for(int v = 1; v <= x[i] && i + v * d[i] <= n; ++v){
                add(dp[i + v * d[i]], dp[i]);
            }
        }
        else{
            if(d[i] == 0) continue;
            add(sum[d[i]][i % d[i]], dp[i]);
            if(i + d[i] * (x[i] + 1) <= n) Del[i + d[i] * (x[i] + 1)].pb(i);
        }
    }
    int ans = 0;
    fis(i, 1, n) add(ans, dp[i]);
    cout << ans << ed;
    // [i + d[i], i + d[i] * x[i]]

    return 0;
}

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