Submission #851906

#	Time	Username	Problem	Language	Result	Execution time	Memory
851906		vjudge1	Magneti (COCI21_magneti)	C++17	10 / 110	1 ms	604 KiB

Main

#pragma GCC optimize("unroll-loops,Ofast,O3")
#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define spc << " " <<
#define endl "\n"
#define all(x) x.begin(), x.end()
#define ll long long
#define int long long
#define ii pair<int,int>
#define vi vector<int>
#define vii vector<ii>
#define st first
#define nd second
#define inf 1000000009
#define MOD 1000000007
using namespace std;




int fact[20005];

int mult(int x, int y){
    return ((x%MOD)*(y%MOD))%MOD;
}
int add(int x, int y){
    return (x+y)%MOD;
}
int sub(int x, int y){
    if((x-y)<0) return x-y+MOD;
    return x-y;
}
int fst(int base, int p){
    int res=1;
    while(p>0){
        if(p%2){
            res = mult(res, base);
            p--;
        }
        else{
            base = mult(base, base);
            p/=2;
        }
    }
    return res;
}
int divi(int x, int y){
    y = fst(y, MOD-2);
    return mult(x, y);
}







void solve(){
    fact[0]=1;
    for(int i=1; i<=20003; i++) fact[i] = mult(fact[i-1], i);

    int n,l; cin >> n >> l;


    if(n<=10 && 0){
        int r[n+1];
        for(int i=1; i<=n; i++) cin >> r[i];

        int arr[n];
        for(int i=1; i<=n; i++) arr[i-1]=i;

        int ans=0;
        do{
            int cur=1;
            for(int i=0; i<n-1; i++){
                int ptr=arr[i], ptr2=arr[i+1];
                cur += max(r[ptr], r[ptr2]);
            }
            //cerr << cur << endl;
            if(cur>l) continue;
            int k = l-cur;
            ans = add(ans, divi(fact[add(n, k)], mult(fact[k], fact[n])));

        } while(next_permutation(arr, arr+n));
        cout << ans << endl;

    }
    else{
        int r;
        for(int i=1; i<=n; i++) cin >> r;
        if(mult((n-1), r)+1 > l){
            cout << 0 << endl;
            return;
        }
        int k = sub(l, mult((n-1), r)+1);
        int ans = divi(fact[add(n, k)], fact[k]);
        cout << ans << endl;
    }
}



signed main(){
    ios_base::sync_with_stdio(false);cin.tie(0);
    #ifdef Local
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    #endif

    ll t=1;
    //cin >> t;
    while(t--) solve();
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 50