Rotate Array | Problem No. 189 | LeetCode

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Given an array, rotate the array to the right by k steps, where k is non-negative.

Follow up:

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?

Example 1:

Input: nums = [1,2,3,4,5,6,7], 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: nums = [-1,-100,3,99], 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]

Constraints:

1 <= nums.length <= 2 * 104 -231 <= nums[i] <= 231 - 1 0 <= k <= 105 Accepted

class Solution {
  public void rotate(int[] nums, int k) {
    // speed up the rotation
    k %= nums.length;
    int temp, previous;
    for (int i = 0; i < k; i++) {
      previous = nums[nums.length - 1];
      for (int j = 0; j < nums.length; j++) {
        temp = nums[j];
        nums[j] = previous;
        previous = temp;
      }
    }
  }
}

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