Submission #1072785

#	Time	Username	Problem	Language	Result	Execution time	Memory
1072785		12345678	Tortoise (CEOI21_tortoise)	C++17	18 / 100	9 ms	1112 KiB

tortoise

#include <bits/stdc++.h>

using namespace std;

const int nx=305;

int n, a[nx], l[nx], r[nx], lst=-1, dp[nx][nx], res, cnt;

int cost(int a, int b)
{
    int mn=1e9;
    if (l[a]!=-1) mn=min(mn, abs(a-l[a])+abs(b-l[a]));
    if (r[a]!=-1) mn=min(mn, abs(a-r[a])+abs(b-r[a]));
    return mn;
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n;
    for (int i=1; i<=n; i++) cin>>a[i];
    for (int i=1; i<=n; i++)
    {
        if (a[i]==-1) lst=i;
        if (a[i]==1) l[i]=lst, cnt++;
    }
    lst=-1;
    for (int i=n; i>=1; i--)
    {
        if (a[i]==-1) lst=i;
        if (a[i]==1) r[i]=lst;
    }
    for (int i=1; i<=n; i++)
    {
        if (a[i]==1)
        {
            for (int j=1; j<=n; j++) dp[i][j]=1e9;
            dp[i][1]=i-1;
            for (int j=1; j<i; j++)
            {
                if (a[j]==1)
                {
                    for (int k=1; k<=i; k++)
                    {
                        //if (i==3&&j==2&&k==2) cout<<"debug "<<dp[j][k]<<' '<<cost(j, i)<<'\n';
                        //if (i==3&&k+1==3) cout<<"j "<<j<<' '<<dp[j][k]+cost(j, i)<<' '<<2*(i-1)<<'\n';
                        if (dp[j][k]+cost(j, i)<=2*(i-1)) dp[i][k+1]=min(dp[i][k+1], dp[j][k]+cost(j, i));
                    }
                }
            }
            //cout<<"dp "<<i<<" : ";
            for (int j=1; j<=i; j++) 
            {
                //if (dp[i][j]==1e9) cout<<-1<<' ';
                //else cout<<dp[i][j]<<' ';
                if (dp[i][j]<1e9) res=max(res, j);
            }
            //cout<<'\n';
        }
    }
    cout<<cnt-res;
}

• Subtask 1: 8 / 8
• Subtask 2: 10 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 25
• Subtask 5: 0 / 27