SelectionSort.java

public class SelectionSort {

    private SelectionSort(){}

    public static <E extends Comparable<E>> void sort(E[] arr){

        // arr[0...i) 是有序的；arr[i...n) 是无序的
        for(int i = 0; i < arr.length; i ++){

            // 选择 arr[i...n) 中的最小值
            int minIndex = i;
            for(int j = i; j < arr.length; j ++){
                if(arr[j].compareTo(arr[minIndex]) < 0)
                    minIndex = j;
            }

            swap(arr, i, minIndex);
        }
    }

    private static <E> void swap(E[] arr, int i, int j){

        E t = arr[i];
        arr[i] = arr[j];
        arr[j] = t;
    }

    public static void main(String[] args){

        Integer[] arr = {1, 4, 2, 3, 6, 5};
        SelectionSort.sort(arr);
        for(int e: arr)
            System.out.print(e + " ");
        System.out.println();

        Student[] students = {new Student("Alice", 98),
                              new Student("Bobo", 100),
                              new Student("Charles", 66)};
        SelectionSort.sort(students);
        for(Student student: students)
            System.out.print(student + " ");
        System.out.println();
    }
}