一、问题描述
Rotate an array of n elements to the right by k steps.
For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7]
is
rotated to [5,6,7,1,2,3,4]
.
Note:
Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.
二、问题分析
注意循环一圈后回到原出发点的情况,例如,数组长度为6,k=2:0-->2-->4-->0,会造成只有下标为0,2,4,的几个数再不停交换。
三、算法代码
public class Solution {
public void rotate(int[] nums, int k) {
int index = 0;
int distance = 0;
int cur = 0;
for (int i = 0; i < nums.length; i++){
int next = (index+k)%nums.length;
int temp = nums[next];
nums[next] = nums[cur];
nums[cur] = temp;
index = next;
distance=(distance+k)%nums.length;
if (distance == 0){
index = (index+1)%nums.length;
cur = index;
}
}
}
}