Insertion sort and selection sort benchmark

InsertionSortAndSelectionSort.java

import java.util.concurrent.ThreadLocalRandom;
import java.util.stream.IntStream;

public class InsertionSortAndSelectionSort {

    public static void main(String[] args) {
        runBenchmarkN(1000);
        runBenchmarkN(10000);
        runBenchmarkN(100000);
    }

    private static void runBenchmarkN(int n) {
        println(String.format("--- n = %s ---", n));
        println();

        println("Random Array");
        int[] randomIntArrayN = getRandomIntArray(n);
        benchmark("InsertionSort", () -> insertionSort(randomIntArrayN.clone()));
        benchmark("SelectionSort", () -> selectionSort(randomIntArrayN.clone()));
        println();

        println("Ordered Array");
        int[] orderedIntArrayN = getOrderedIntArray(n);
        benchmark("InsertionSort", () -> insertionSort(orderedIntArrayN.clone()));
        benchmark("SelectionSort", () -> selectionSort(orderedIntArrayN.clone()));
        println();
    }


    private static void println(String s) {
        System.out.println(s);
    }

    private static void println() {
        System.out.println();
    }

    private static void benchmark(String label, Runnable runnable) {
        long start = System.currentTimeMillis();
        runnable.run();
        long end = System.currentTimeMillis();
        println(String.format("%s: %s s", label, (end - start) / 1000.0));
    }

    private static int[] getRandomIntArray(int n) {
        return ThreadLocalRandom.current().ints(0, Integer.MAX_VALUE).limit(n).toArray();
    }

    private static int[] getOrderedIntArray(int n) {
        int[] i = {0};
        return IntStream.generate(() -> i[0]++).limit(n).toArray();
    }

    private static void insertionSort(int[] arr) {
        for (int i = 1; i < arr.length; i++) {
            int j = i - 1;
            int t = arr[i];
            for (; j >= 0; j--) {
                if (arr[j] <= t) {
                    break;
                }
            }
            if (j < i - 1) {
                int k = i;
                while (k != j + 1) {
                    arr[k] = arr[k - 1];
                    k--;
                }
                arr[j + 1] = t;
            }
        }
    }

    private static void selectionSort(int[] arr) {
        for (int i = 0; i < arr.length - 1; i++) {
            int c = i;
            for (int j = i + 1; j < arr.length; j++) {
                if (arr[j] < arr[c]) {
                    c = j;
                }
            }
            if (c != i) {
                int t = arr[i];
                arr[i] = arr[c];
                arr[c] = t;
            }
        }
    }
}