编程之美2.17数组循环移位Java版_TT285955925的博客

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package Test;

import java.util.Arrays;


/**
 *
 * 2.17 数组循环移位
 */
public class ReverseArray {
    public static void main(String[] args) {
        int[] array = new int[]{1,2,3,4,5,6,7,8};
        //解法一
        int[] a1 = reverse_array1(array,array.length,6);
        System.out.println(Arrays.toString(a1));
        //解法二
        int[] array2 = new int[]{1,2,3,4,5,6,7,8};
        int[] a2 = reverse_array2(array2,array2.length,6);
        System.out.println(Arrays.toString(a2));
        //解法三 多用了一个数组的办法，附件变量超过两个
        int[] array3 =new int[]{1,2,3,4,5,6,7,8};
        int[] a3 = reverse_array3(array3,array3.length,6);
        System.out.println(Arrays.toString(a3));
    }

    private static int[] reverse_array1(int[] array,int n ,int k) {
        k %=n;
        while(k>0){
            int t = array[n-1];
            for(int i =n-1;i>0;i--)
                array[i]=array[i-1];
            array[0] = t;
            k--;
        }
        return array;
    }

    private static int[] reverse_array2(int[] array, int n, int k) {
       k %=n;
       reverse(array,0,n- k-1);
       reverse(array,n-k,n-1);
       reverse(array,0,n-1);
       return array;
    }

    private static void reverse(int[] array, int b, int e) {
        for(;b<e;b++,e--){
            int tmp = array[e];
            array[e] = array[b];
            array[b] =  tmp;
        }
    }

    private static int[] reverse_array3(int[] array, int n, int k) {
        k %=n;
        int[] a = new int[n];
        for(int i =0;i<n;i++){
            int num = i+k>=n?((i+k)%n):(i+k);
            a[num] = array[i];
        }
        return a;
    }
}
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