[Solved] Calculate the mode of the numbers in java

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Under the assumption the highest number in the input data is some reasonable number, this code will find the modes. I’m sure there is a way to make it all Java 8 streams, but I’m still working to master them.

    public static void main(String[] args)
{
    final int data[] = new int[] {24, 26, 28, 29, 30, 32, 32, 35, 37, 38, 38, 40, 41, 42, 43, 44, 44, 45, 45, 46, 47, 47, 47, 48, 48, 48, 48, 49, 49, 50, 50, 50, 51, 52, 52, 53, 53, 53, 53, 53, 54, 54, 56, 56, 56, 57, 57, 57, 57, 58, 58, 58, 59, 60, 60, 60, 60, 61, 61, 61, 61, 62, 62, 62, 62, 62, 63, 64, 64, 64, 65, 65, 65, 66, 66, 66, 67, 67, 67, 67, 67, 68, 70, 71, 71, 72, 72, 72, 73, 73, 73, 75, 76, 76, 76, 76, 77, 77, 77, 77, 77, 78, 78, 78, 78, 78, 80, 80, 80, 81, 82, 83, 84, 85, 85, 85, 85, 85, 88, 89, 91, 91, 93, 96, 97};
    final int MAX = 100;

    final int[] counts = new int[MAX];

    for (int i = 0; i < data.length; ++i) {
        int num = data[i];
        counts[num]++;
    }
    
    OptionalInt oi = Arrays.stream(counts).max();
    int cnt = oi.getAsInt();

    System.out.println("Modes for input data");
    for (int i = 0; i < counts.length; ++i) {
        if (counts[i] == cnt) {
            System.out.print(String.format("%3d", i));
        }
    }
    System.out.println();
   }

Test Output:

Modes for input data

53 62 67 77 78 85

Edit: the MAX can be found dynamically by doing something akin to the following. Again, the assumption is this maximum value is something reasonable, but the OP’s question restricted the ability to use Map or similar objects.

final int MAX = Arrays.stream(data).max().getAsInt();
    
final int[] counts = new int[MAX+1];

solved Calculate the mode of the numbers in java