package question;

import java.util.Arrays;

public class Question189 {
 public static void main(String[] args) {
 //[1,2,3,4,5,6,7] 和 k = 3
 int[] nums = new int[]{-1,-100,3,99};
 int k = 2;
 new Question189().rotate(nums, k);
 for (int num : nums) {
 System.out.println(num);
 }
 }

 public void rotate(int[] nums, int k) {
 int[] tmp = Arrays.copyOf(nums, nums.length);
 for (int i = 0; i < tmp.length; i++) {
 nums[(i + k) % nums.length] = tmp[i];
 }
 }

 public void rotate2(int[] nums, int k) {
 if (nums == null || nums.length <= 0) return;
 int x = 0;
 int cnt=0;
 while (cnt<nums.length) {
 int f=x;
 int tmp=nums[x];
 while (true) {
 x=(x+k)%nums.length;
 int t=nums[x];
 nums[x]=tmp;
 tmp=t;
 cnt++;
 if (f==x) break;
 }
 x++;
 }
 }

 public void rotate3(int[] nums, int k) {
 k%=nums.length;
 int count=gcd(k, nums.length);
 for (int i = 0; i < count; i++) {
 int x=i;
 int tmp=nums[x];
 do {
 x=(x+k)%nums.length;
 int t=nums[x];
 nums[x]=tmp;
 tmp=t;
 } while (x!=i);
 }
 }

 private int gcd(int a,int b){
 return b==0?a:gcd(b,a%b);
 }

 public void rotate4(int[] nums, int k) {
 k%=nums.length;
 re(nums, 0, nums.length-1);
 re(nums, 0, k-1);
 re(nums, k, nums.length-1);
 }

 private void re(int[] nums, int from, int to) {
 while (from<to) {
 int t=nums[from];
 nums[from]=nums[to];
 nums[to]=t;
 from++;
 to--;
 }
 }
}