package com.test;

import java.util.Arrays;

public class SelectSort {
   
	//选择排序原理即是:
	//遍历元素找到一个最小(或最大)的元素,把它放在第一个位置;
	//然后再在剩余元素中找到最小(或最大)的元素,把它放在第二个位置;
	//依次下去，完成排序.
	public static void main(String[] args) {
   
		
		//由小到大
		int[] arr={
   72, 7, 65, 72, 91, 91, 91, 89, 65, 58, 87, 91, 53, 82, 71, 93, 76, 68};
		select_sort_small_to_big(arr);
		System.out.println(Arrays.toString(arr));
		
		
		//由大到小
		arr = new int[]{
   72, 7, 65, 72, 91, 91, 91, 89, 65, 58, 87, 91, 53, 82, 71, 93, 76, 68};
		select_sort_big_to_small(arr);
		System.out.println(Arrays.toString(arr));
	}
	
	public static int[] select_sort_small_to_big(int arr[]) {
   
		for(int i = 0; i < arr.length - 1; i++) {
   
			int min  = arr[i];
			int min_pos = i;
			for(int j = i + 1; j < arr.length; j++) {
   
				if(arr[j] < min) {
   
					min = arr[j];
					min_pos = j; 
				}
			}
			if(min_pos != i) {
   
				arr[min_pos] = arr[i];
				arr[i] = min;
			}
		}
		return arr;
	}
	
	public static int[] select_sort_big_to_small(int[] arr) {
   
		for(int i = 0; i < arr.length - 1; i++) {
   
			int max = arr[i];
			int max_pos = i;
			for(int j = i + 1; j < arr.length; j++) {
   
				if(arr[j] > max) {
   
					max = arr[j];
					max_pos = j; 
				}
			}
			if(max_pos != i) {
   
				arr[max_pos] = arr[i];
				arr[i] = max;
			}
		}
		return arr;
	}
}