package com.interview.number;
/**
* http://www.geeksforgeeks.org/length-of-the-longest-arithmatic-progression-in-a-sorted-array/
*/
public class ArithemeticProgressionExists {
public boolean exists(int input[]){
for(int i=1; i < input.length-1; i++){
int j = i-1;
int k = i+1;
while(j >=0 && k <= input.length-1){
if(input[i]*2 == input[j] + input[k]){
return true;
}else if(input[i]*2 > input[j] + input[k]){
k++;
}else{
j--;
}
}
}
return false;
}
public static void main(String args[]){
int input[] = {1,3,6,7,10,11,15};
ArithemeticProgressionExists ape = new ArithemeticProgressionExists();
System.out.println(ape.exists(input));
}
}