Submission #211754

#	Time	Username	Problem	Language	Result	Execution time	Memory
211754		nafis_shifat	Building 4 (JOI20_building4)	C++14	100 / 100	1288 ms	34920 KiB

building4

#include<bits/stdc++.h>
#define pii pair<int,int>
#define ll long long
using namespace std;
int main()
{
	
	int n;
	cin>>n;

	int dp1[2*n+1][2]={};
	int dp2[2*n+1][2]={};
    
    for(int i=0;i<=2*n;i++)dp1[i][0]=dp1[i][1]=1e9+9;
	memset(dp2,-1,sizeof(dp2));


	int a[2*n+1],b[2*n+1];

	for(int i=1;i<=2*n;i++)cin>>a[i];
	for(int i=1;i<=2*n;i++)cin>>b[i];

	dp1[1][0]=dp2[1][0]=1;
    dp1[1][1]=dp2[1][1]=0;




    for(int i=2;i<=2*n;i++)
    {
    	if(a[i-1]<=a[i])
    	{
    		dp1[i][0]=dp1[i-1][0]+1;
    		dp2[i][0]=dp2[i-1][0]+1;
    	}

    	if(b[i-1]<=a[i])
    	{
    		dp1[i][0]=min(dp1[i][0],dp1[i-1][1]+1);
    		dp2[i][0]=max(dp2[i][0],dp2[i-1][1]+1);
    	}

    	if(a[i-1]<=b[i])
    	{
    		dp1[i][1]=dp1[i-1][0];
    		dp2[i][1]=dp2[i-1][0];
    	}

    	if(b[i-1]<=b[i])
    	{
    		dp1[i][1]=min(dp1[i][1],dp1[i-1][1]);
    		dp2[i][1]=max(dp2[i][1],dp2[i-1][1]);

    	}
    	
    	
    	

    }
    
   // cout<<dp2[2*n][0]<<endl;


    int cr=2*n;

    int nx=0;

    int tx=n;


    vector<int> r;

    if(dp1[cr][0]<=n && dp2[cr][0]>=n)
    {
    	r.push_back(0);
    	tx--;
    	if(dp1[cr-1][0]<=tx && dp2[cr-1][0]>=tx && a[cr-1]<=a[cr])nx=0;
    	else nx=1;
    }
    else if(dp1[cr][1]<=n && dp2[cr][1]>=n)
    {
    	r.push_back(1);
    	if(dp1[cr-1][0]<=n && dp2[cr-1][0]>=n && a[cr-1]<=b[cr])nx=0;
    	else nx=1;
    }
    else
    {
    	cout<<-1<<endl;
    	return 0;
    }

    cr--;


    while(cr)
    {
    	r.push_back(nx);
    	if(nx==0 && tx>0)
    	{
    		tx--;
    		if(dp1[cr-1][0]<=tx && dp2[cr-1][0]>=tx && a[cr-1]<=a[cr])nx=0;
    		else nx=1;
    		cr--;
    		continue;
    	}
    	else
    	{
    		if(dp1[cr-1][0]<=tx && dp2[cr-1][0]>=tx && a[cr-1]<=b[cr])nx=0;
    		else nx=1;
    		cr--;
    		continue;

    	}
    }

    reverse(r.begin(),r.end());
    
    for(int i=0;i<r.size();i++)
    {
    	if(r[i]==0)cout<<"A";
    	else cout<<"B";
	}


	return 0;
}

Compilation message (stderr)

building4.cpp: In function 'int main()':
building4.cpp:118:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<r.size();i++)
                 ~^~~~~~~~~

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