@Override public void sort(int[] numbers) {
    validateInput(numbers);

    int i;
    for (i = 1; i < numbers.length; i++) {
      int tmp = numbers[i];
      int j = i;
      while (j > 0 && numbers[j - 1] > tmp) {
        numbers[j] = numbers[j - 1];
        j--;
      }
      numbers[j] = tmp;
    }
  }
Insertion sort is a simple sorting algorithm that is relatively efficient for small lists and
mostly sorted lists, and often is used as part of more sophisticated algorithms. It works by
taking elements from the list one by one and inserting them in their correct position into a
new sorted list. In arrays, the new list and the remaining elements can share the array's
space, but insertion is expensive, requiring shifting all following elements over by one.
src/main/java/com/github/pedrovgs/problem76/InsertionSort.java