package ch10;

/**
 * 簡單選擇排序
 * @author songjie
 *
 */
public class SelectSort {
	public static <T extends Comparable> boolean selectSort(T[] t){
		if(t==null || t.length <= 1) return true;
		for(int i = 0; i<t.length-1; i++){
			int pos = selectMinKey(t, i);
			T temp = t[i];
			t[i] = t[pos];
			t[pos] = temp;
			
		}
		return true;
	}
	
	/**
	 * 返回最小的元素的索引
	 * @param t
	 * @param start:開始的索引
	 * @return
	 */
	private static <T extends Comparable> int selectMinKey(T[] t, int startPos) throws IllegalArgumentException{
		if(t==null || t.length-1-startPos<=0) throw new IllegalArgumentException("引數傳遞不正確！");
		int pos = startPos;
		T min = t[pos];
		for(int i=pos; i<=t.length-1 ;i++){
			if(t[i].compareTo(min) < 0){
				min = t[i];
				pos = i;
			}
		}	
		return pos;
	}
	
	public static void main(String[] args) {
		Integer[] arr = new Integer[]{1,2,5,7,4,2,3,9,7};
		SelectSort.selectSort(arr);
		for(int i : arr){
			System.out.println(i);
		}
	}
}