翻转数组

Posted 2021-02-19 shuimuzhushui

在看Collections工具类代码时，发现翻转数组的逻辑，感觉很有趣。思想：折半交换

public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[] n = new int[] {1,2,3,4,5,4,6,7,8,9};
        int size = n.length;
        for (int i=0, mid=size>>1, j=size-1; i<mid; i++, j--)
            swap(n, i, j);
        for(int i : n) {
            System.out.print(i + " ");
        }
    }
    
    private static void swap(int[] arr, int i, int j) {
        int tmp = arr[i];
        arr[i] = arr[j];
        arr[j] = tmp;
    }