[FIXED] Java Collections Frequency Argument

Issue

I am trying to solve the problem of determining how many pairs of occurrences in the array ar there are for each integer in the array:

class Result {

    /*
     * Complete the 'sockMerchant' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts following parameters:
     *  1. INTEGER n
     *  2. INTEGER_ARRAY ar
     */


    public static int sockMerchant(int n, List<Integer> ar) {
    // Write your code here
    
    for(int i = 0; i<n ; i++) {

    int occurrences[];
    occurrences[i] = Collections.frequency(ar, ar[i]);
    
}

    int pairs = 0;

for(int j = 0; j<n; j++) {
    
    pairs = pairs + (0.5*occurrences[j]) ;
    }



    return pairs;
}
    }

I keep getting the following two errors and after reviewing the Java API and various online resources cannot determine the issue. Can someone advise?

Solution.java:31: error: array required, but List<Integer> found
    occurrences[i] = Collections.frequency(ar, ar[i]);
                                                 ^
Solution.java:39: error: cannot find symbol
    pairs = pairs + (0.5*occurrences[j]) ;
                         ^
  symbol:   variable occurrences
  location: class Result
2 errors

Solution

Great idea to google "Java access list element"

  public static int sockMerchant(int n, List<Integer> ar) {
    // Write your code here
        int occurrences[];

        int pairs = 0;

 
       Set<Integer> distinct = new HashSet<>(ar);
        for (Integer s: distinct) {


  pairs +=  0.5*Collections.frequency(ar, s);
        }
    

/*for(int j = 0; j<n; j++) {
    
    pairs = pairs + (0.5*occurrences[j]) ;
    }*/
    return pairs;
}
    }

Answered By - don