Submission #715854

#	Time	Username	Problem	Language	Result	Execution time	Memory
715854		bin9638	The Big Prize (IOI17_prize)	C++17	90 / 100	79 ms	2840 KiB

prize

#include<bits/stdc++.h>

#ifndef SKY
#include "prize.h"
#endif // SKY

using namespace std;
#define N 200010
#define ll long long
#define ii pair<int,int>
#define fs first
#define sc second
#define pb push_back
#define iii pair<int,ii>

int n,lolipop;
int ktr[N];
ii f[N];

#ifdef SKY
int p[N];
vector<int> ask(int i)
{
    cout<<"ask "<<i<<endl;
    vector<int>res(2,0);
    for(int j=0;j<i;j++)
        if(p[j]<p[i])
            res[0]++;
    for(int j=i+1;j<n;j++)
        if(p[j]<p[i])
            res[1]++;
    // cout<<i<<endl;
      //  for(int j=0;j<n;j++)cout<<p[j]<<" ";cout<<endl;
      //  cout<<res[0]<<" "<<res[1]<<endl;
    return res;
}
#endif // SKY

int query=0;

vector<int>myAsk(int i)
{
     query++;
    assert(query<=1e4);
    if(ktr[i]!=-1)
        return {f[i].fs,f[i].sc};
    vector<int>res=ask(i);
    ktr[i]=1;
    f[i]={res[0],res[1]};
    return res;
}

vector<ii>lis;

void solve(int l,int r,int left_child,int right_child)
{
    if(l>r)
        return;
    int mid=(l+r)/2,v=mid,u=mid-1;
    while(1)
    {
        vector<int>s;
        if(u>=l)
        {
            s=myAsk(u);
            if(s[0]+s[1]!=lolipop)
            {
                lis.pb({u,s[0]+s[1]});
                if(s[0]==0)
                {
                    u=l-1;
                }
                if(s[1]==0)
                {
                    v=r+1;
                }
                u--;
            }else
            {
                if(s[0]-left_child!=0)
                {
                    solve(l,u-1,left_child,s[1]);
                }
                if(s[1]-right_child!=0)
                {
                    solve(v,r,s[0],right_child);
                }
                return;
            }
        }
        if(v<=r)
        {
            s=myAsk(v);
            if(s[0]+s[1]!=lolipop)
            {
                lis.pb({v,s[0]+s[1]});
                  if(s[0]==0)
                {
                    u=l-1;
                }
                if(s[1]==0)
                {
                    v=r+1;
                }
                v++;
            }else
            {
                if(s[0]-left_child!=0)
                {
                    solve(l,u,left_child,s[1]);
                }
                if(s[1]-right_child!=0)
                {
                    solve(v+1,r,s[0],right_child);
                }
                return;
            }
        }
        if(u<l&&v>r)
            return;
    }
   /* for(int i=mid;i<=r;i++)
    {
        vector<int>s=myAsk(i);
        if(s[0]+s[1]!=lolipop)
        {
            lis.pb(i);
        }else
        {
            if(s[0]-left_child!=0)
            {
                solve(l,mid-1,left_child,s[1]);
            }
            if(s[1]-right_child!=0)
            {
                solve(i+1,r,s[0],right_child);
            }
            return;
        }
    }
    for(int i=mid-1;i>=l;i--)
    {
        vector<int>s=myAsk(i);
        if(s[0]+s[1]!=lolipop)
        {
            lis.pb(i);
        }else
        {
            if(s[0]-left_child!=0)
            {
                solve(l,i-1,left_child,s[1]);
            }
        }
    }*/
}

int find_best(int cc)
{
    memset(ktr,-1,sizeof(ktr));
    n=cc;
    lis.clear();
    if(n<=500)
    {
        for(int i=0;i<n;i++)
        {
            vector<int>s=myAsk(i);
            if(s[0]==0&&s[1]==0)
                return i;
        }
    }
    lolipop=0;
    for(int i=0;i<sqrt(n)+100;i++)
    {
        vector<int>s=myAsk(i);
        lolipop=max(lolipop,s[0]+s[1]);
    }
    solve(0,n-1,0,0);
    for(auto i:lis)
    {
        if(i.sc==0)
            return i.fs;
    }
}

#ifdef SKY
int main()
{
    freopen("A.inp","r",stdin);
    freopen("A.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    int n;
    cin>>n;
    for(int i=0;i<n;i++)
        cin>>p[i];
    cout<<find_best(n);
    cout<<endl<<query<<endl;
    return 0;
}
#endif // SKY

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:183:1: warning: control reaches end of non-void function [-Wreturn-type]
  183 | }
      | ^

• Subtask 1: 20 / 20
• Subtask 2: 70 / 80