# Poj Solution 1058

```http://poj.org/problem?id=1058

//* @author:
import java.util.*;
public class Main{
String result[][];
char c[]={'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P'};

boolean used[];

public Main(String result[][]){
this.result=result;

}

public static void main(String args[]){
Scanner sc=new Scanner(System.in);

while(true){
String result[][]=new String[5][4];

for(int i=0;i< 5;i++)
for(int j=0;j< 4;j++){
if(i>=3)
result[i][j]="";
else
result[i][j]=sc.next();
}

Main m=new Main(result);

int r=0;
for(int x=3;x<=4;x++){
if(!m.doIt(x)){ r+=1; break;}
}
if(r==0) m.show();
}
}

private void show(){
for(int i=0;i< 5;i++){
for(int j=0;j< 4;j++){
System.out.print(result[i][j]+" ");
}
System.out.println();
}
System.out.println();
}

private boolean ch(String s1,String s2){
int x=0;
for(int i=0;i< s1.length();i++)
for(int j=0;j< s2.length();j++){
if(s1.charAt(i)==s2.charAt(j)) x++;
if(x>=2) return true;
}
return false;
}

private boolean check(StringBuffer temp){
String s=temp.toString();
for(int i=0;i< 5;i++)
for(int j=0;j< 4;j++){
if(result[i][j]!=null&&ch(result[i][j],s))
return false;
}
return true;
}

public boolean doIt(int x){
used=new boolean[16];
int sum=0;
int y=0;

for(int i=0;i< 16;i++)
for(int j=i+1;j< 16;j++)
for(int k=j+1;k< 16;k++)
for(int l=k+1;l< 16;l++){
if(!used[i]&&!used[j]&&!used[k]&&!used[l]){
StringBuffer s=new StringBuffer("");
s.append(c[i]).append(c[j]).append(c[k]).append(c[l]);
if(check(s)){
used[i]=true;used[j]=true;used[k]=true;used[l]=true;
result[x][y]=s.toString();

y=y+1;
sum=sum+1;
}
}
}
if(sum< 4){
System.out.println("It is not possible to complete this schedule.");
System.out.println();
return false;
}
return true;
}

}
```
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