Given an array, rotate the array to the right by k steps, where k is non-negative.
Example 1:
Input: [1,2,3,4,5,6,7] and k = 3
Output: [5,6,7,1,2,3,4]
Explanation:
rotate 1 steps to the right: [7,1,2,3,4,5,6]
rotate 2 steps to the right: [6,7,1,2,3,4,5]
rotate 3 steps to the right: [5,6,7,1,2,3,4]
Example 2:
Input: [-1,-100,3,99] and k = 2
Output: [3,99,-1,-100]
Explanation:
rotate 1 steps to the right: [99,-1,-100,3]
rotate 2 steps to the right: [3,99,-1,-100]
Note:
Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.
Could you do it in-place with O(1) extra space?
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class Solution {
public void rotate(int[] nums, int k) {
if(nums == null || nums.length == 0) return;
int n = nums.length;
k = k % n;
reverse(nums,0,n-k-1);
reverse(nums,n-k,n-1);
reverse(nums,0,n-1);
}
public void reverse(int[] nums,int start, int end){
while(start < end){
int tmp = nums[start];
nums[start] = nums[end];
nums[end] = tmp;
start++;
end--;
}
}
}
