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189 Rotate Array

/**
 *
 * Ashish Patel
 * e: ashishsushilPatel@gmail.com
 * w: https://ashish.me
 *
 */

/*
 * 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]
 */

function rotateArray(nums, k) {
  k %= nums.length
  function reverse(s, e) {
    while (s < e) {
      let temp = nums[s]
      nums[s] = nums[e]
      nums[e] = temp
      s++
      e--
    }
  }
  reverse(0, nums.length - 1)
  reverse(0, k - 1)
  reverse(k, nums.length - 1)
  return nums
}

test('rotate Array', () => {
  expect(rotateArray([1, 2, 3, 4, 5, 6, 7], 3)).toEqual([5, 6, 7, 1, 2, 3, 4])
  expect(rotateArray([-1], 2)).toEqual([-1])
})

Created 2020-04-11T23:13:06+00:00, updated 2020-04-16T21:26:07+00:00 · History · Edit