Submission #900963

#	Time	Username	Problem	Language	Result	Execution time	Memory
900963		simona1230	A Difficult(y) Choice (BOI21_books)	C++17	20 / 100	118 ms	1376 KiB

books

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

long long n,k,a,s;
long long x[120001];

void know_all()
{
    for(long long i=1;i<=n;i++)
    {
        x[i]=skim(i);
    }

    long long fk=0,fs=0,fsidx=0;
    for(int i=1;i<=n;i++)
    {
        if(i<k)fk+=x[i];
        if(x[i]>=a)
        {
            fs=x[i];
            fsidx=i;
            break;
        }
    }

    if(fs+fk>=a&&fs+fk<=2*a)
    {
        vector<int> ans;
        for(int i=1;i<k;i++)
            ans.push_back(i);
        ans.push_back(fsidx);
        answer(ans);
        return;
    }

    long long sum=0;
    for(int i=1;i<=n;i++)
    {
        sum+=x[i];
        if(i>k)sum-=x[i-k];
        if(i>=k&&sum>=a&&sum<=2*a)
        {
            vector<int> ans;
            for(int j=i-k+1;j<=i;j++)
                ans.push_back(j);
            answer(ans);
            return;
        }
    }

    impossible();
}

void solve(int N,int K,long long A,int S)
{
    n=N;
    k=K;
    a=A;
    s=S;

    if(s==n)
    {
        know_all();
        return;
    }

    int l=1,r=n-k+1;
    while(l<=r)
    {
        int m=(l+r)/2;
        long long ll=skim(m);
        long long rr=skim(m+k-1);
        long long minn=ll*(2*ll+k-2)/2+rr;
        long long maxx=rr*(2*rr-k+2)/2+ll;
        if(minn>=a&&maxx<=2*a)
        {
            vector<int> ans;
            for(int i=m;i<=m+k-1;i++)
                ans.push_back(i);
            answer(ans);
            return;
        }
        if(minn<a&&maxx>2*a)
        {
            impossible();
            return;
        }
        if(minn<a)l=m+1;
        else r=m-1;
    }
    impossible();
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20