Maximum K Greater than Elements

Maximum K Greater than Elements

  December 04, 2017    

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Problem: 

Given an array of positive integers, Your task is to  find maximum possible value K such that the array has at-least K elements that are greater than or equal to K

Idea is to save frequency of number 
1) if no. is > number
++freq of n
else
freq of number

Code:

import java.util.*;
import java.lang.*;
import java.io.*;
class hackerranksolutionc
 {
     public static int getK(int arr[],int n)
{
int freq[]=new int[n+1];
for(int i=0;i<n;++i)
{
if(arr[i]>=n)
++freq[n];
else
++freq[arr[i]] ;
}
int sum=0;
for(int i=n;i>0;--i)
{
sum+=freq[i];
if(sum>=i)
return i;
}
return 0;
}
public static void main (String[] args)
{
Scanner ab=new Scanner(System.in);
int t=ab.nextInt();
while(t-->0)
{
    int n=ab.nextInt();
    int arr[]=new int[n];
    for(int i=0;i<n;++i)
    arr[i]=ab.nextInt();
    System.out.println(getK(arr,n));
}
}
}