Java 冒泡排序優化

優化後對已經排好序的數組排序的時間複雜度爲O(1) 

public class Test {
	//冒泡排序
	public static void main(String[] args) {
		int arr[] = {1,2,3,4,5};
		boolean flag = false;//假定數組是已經排好序的
		for (int i = 0; i < arr.length-1; i++) {
			System.out.println("========");
			for (int j = 0; j < arr.length -1 -i; j++) {
				if (arr[j]>arr[j+1]) {
					int temp = arr[j];
					arr[j] = arr[j+1];
					arr[j+1] =temp;
					flag = true;
				}
			}
			if (flag == false) {
				//假設成立，數組是有序的
				break;
			}else {
				flag = false;
			}
		}
		for (int i : arr) {
			System.out.println(i);
		}
	}
}