Submission #1012783

#	Time	Username	Problem	Language	Result	Execution time	Memory
1012783		denislav	Building 4 (JOI20_building4)	C++14	11 / 100	44 ms	32084 KiB

building4

# include <iostream>
# include <vector>
# include <algorithm>
using namespace std;

const int MAX=4e3+11;
int a[2][MAX];
bool dp[2][MAX][MAX];
int n;

vector<char> ve;

void rec(int k, int i, int v)
{
    //cout<<"->"<<k<<" "<<i<<" "<<v-n<<"\n";

    if(k==0) ve.push_back('A');
    else ve.push_back('B');

    if(i==1) return ;

    int d=1;
    if(k==1) d=-1;

    if(v-d>=0 and v-d<=n*2 and dp[0][i-1][v-d]==1 and a[0][i-1]<=a[k][i]) rec(0,i-1,v-d);
    else rec(1,i-1,v-d);
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);

    cin>>n;
    for(int k=0;k<=1;k++)
    {
        for(int i=1;i<=n*2;i++) cin>>a[k][i];
    }

    dp[0][1][n+1]=1;
    dp[1][1][n-1]=1;
    for(int i=1;i<n*2;i++)
    {
        for(int k=0;k<=1;k++)
        {
            for(int v=0;v<=n*2;v++)
            {
                if(dp[k][i][v]==0) continue;

                //cout<<i<<" "<<k<<" "<<v-n<<"\n";

                if(a[k][i]<=a[0][i+1] and v+1<=n*2) dp[0][i+1][v+1]=1;
                if(a[k][i]<=a[1][i+1] and v-1>=0) dp[1][i+1][v-1]=1;
            }
        }
    }

    if(!(dp[0][n*2][n]==1 or dp[1][n*2][n]==1)) {cout<<-1<<"\n";return 0;}

    if(dp[0][n*2][n]==1) rec(0,n*2,n);
    else rec(1,n*2,n);

    reverse(ve.begin(),ve.end());
    for(char x: ve) cout<<x;
    cout<<"\n";

    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 0 / 89