经典算法之直接选择排序（SelectionSort）

java代码实现
public class SelectionSort {
    public static void main(String[] args) {
        Integer[] arr = {9,18,38,2,46,8,43,46,5,12};
        sort(arr);
        System.out.println(Arrays.toString(arr));
    }
    public static void sort(Comparable[] a){
        for (int i = 0;i <= a.length - 2;i++){
            //定义一个变量，记录最小元素的索引
            int minIndex = i;
            for (int j = i + 1;j < a.length;j++){
                //比minIndex与j两个索引处的值的大小
                if (greater(a[minIndex],a[j])){
                    minIndex = j;
                }
            }
            //交换最小元素的所在索引minIndex处的值与索引值为i的元素的值
            swap(a,i,minIndex);
        }
    }
    //比较 v 是否大于 w
    public static boolean greater(Comparable v,Comparable w){
        return v.compareTo(w) > 0;
    }
    //数组元素交换位置
    private static void swap(Comparable[] a,int i,int j){
        Comparable temp;
        temp = a[i];
        a[i] = a[j];
        a[j] = temp;
    }
}

排序前：{9,18,38,2,46,8,43,46,5,12}
排序后：{2,5,8,9,12,18,38,43,46,46}