Poj Solution 1868

http://poj.org/problem?id=1868

/* @author: */
import java.util.Scanner;
public class Main {
  private int n;
  private int a[];

  public Main(int n,int[] a){
   this.n=n;
   this.a=a;
 }
  public boolean doIt(){
   for(int j=1;j< n/2;j++)
   {
    for(int i=j;i< n-j;i++)
    {
         if((a[i-j]-a[i])*(a[i+j]-a[i])< 0)
      {
        return true;
      }
    }
   }
   return false;
  }

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    while(sc.hasNext())
    {    
         int n=0;
         String s=sc.next();
         if(s.endsWith(":"))
          n=Integer.parseInt(s.substring(0,s.length()-1));
         if(n==0) break;
           int a[]=new int[n];
      for(int i=0;i< n;i++){
        int tempno=sc.nextInt();
        a[tempno]=i;
      }
         Main m=new Main(n,a);
      if(!m.doIt())
        System.out.printf("yesn");
      else
        System.out.printf("non");
     }
   }
}