Submission #1110152

#	Time	Username	Problem	Language	Result	Execution time	Memory
1110152		vjudge1	Žarulje (COI15_zarulje)	C++17	100 / 100	356 ms	191816 KiB

zarulje

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define Ls l.top()
#define Rs r.top()
#define calc(x) (fac[mp1[x]+mp2[x]]*inv[mp2[x]]%M*inv[mp1[x]]%M)
const int M=1e9+7,N=1<<18;
int H[N],fac[N],inv[N],res[N],mp1[N],mp2[N];
stack<int>bad[N],l,r;
int qp(int x,int k=M-2){
    if(!k) return 1;
    int y=qp(x,k/2);
    y=y*y%M;
    if(k&1)y=y*x%M;
    return y;
}
signed main(){
    l.push(0),r.push(0);
    cin.tie(0)->sync_with_stdio(0);
    fac[0]=1;
    for(int i=1;i<N;i++)
        fac[i]=fac[i-1]*i%M;
    inv[N-1]=qp(fac[N-1]);
    res[1]=1;
    for(int i=N;--i;)
        inv[i-1]=inv[i]*i%M;
    int n,k;
    cin>>n>>k;
    for(int i=1;i<=n;i++)
        cin>>H[i];
    for(int i=n;i>1;mp2[H[i]]++,r.push(H[i--]))
        while(Rs>H[i])
            bad[i].push(Rs),
            mp2[Rs]--,r.pop();
    for(int i=2;i<=n;i++) {
        res[i]=res[i-1];
        while(Ls>H[i-1])
            res[i]=res[i]*qp(calc(Ls))%M,
            mp1[Ls]--,res[i]=res[i]*calc(Ls)%M,l.pop();
        res[i]=res[i]*qp(calc(Rs))%M,mp2[Rs]--;
        res[i]=res[i]*calc(Rs)%M,r.pop();
        l.push(H[i-1]),res[i]=res[i]*qp(calc(Ls))%M;
        mp1[Ls]++,res[i]=res[i]*calc(Ls)%M;
        while(bad[i].size())
            r.push(bad[i].top()),res[i]=res[i]*qp(calc(Rs))%M,
            mp2[Rs]++,res[i]=res[i]*calc(Rs)%M,bad[i].pop();
    }
    while(k--){
        int x;
        cin>>x;
        cout<<res[x]<<'\n';
    }
}

• Subtask 1: 22 / 22
• Subtask 2: 38 / 38
• Subtask 3: 40 / 40