Question

If I were to implement a code that searchs for the first repeating pair in an array, this code would return the index of the first repeating pair. Using arrays and not array lists or sets.

for example; a=[1,2,3,4,2,1]; This code would return the index of the second 2 that was repeating. Output= 4. Please help

Answer 1

public class lib{
public static void main(String[] args){
int a[]={1,2,3,4,2,1};
int pair[]=new int[2];
boolean flag=false;
for(int i=0;i<a.length-1;i++){
   pair[0]=a[i];
   pair[1]=a[i+1];
   for(int j=i+1;j<a.length-1;j++){
       if((a[j]==pair[0]&&a[j+1]==pair[1])||(a[j]==pair[1]&&a[j+1]==pair[0])){
           System.out.println("index of first repeating pair : "+j);
           flag=true;
           break;
       }
   }
   if(flag==true)break;
}
}
}