189.Rotate_Array.rb

# 189. Rotate Array
# Easy

# 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?


# @param {Integer[]} nums
# @param {Integer} k
# @return {Void} Do not return anything, modify nums in-place instead.
def rotate(nums, k)
    k.times { nums.unshift(nums.pop) }
end

p rotate([1,2,3,4,5,6,7], 3)