[LeetCode] 1470. Shuffle the Array

Given the array nums consisting of 2n elements in the form [x1,x2,...,xn,y1,y2,...,yn].

Return the array in the form [x1,y1,x2,y2,...,xn,yn].

 

Example 1:

Input: nums = [2,5,1,3,4,7], n = 3 Output: [2,3,5,4,1,7] Explanation: Since x1=2, x2=5, x3=1, y1=3, y2=4, y3=7 then the answer is [2,3,5,4,1,7].

Example 2:

Input: nums = [1,2,3,4,4,3,2,1], n = 4 Output: [1,4,2,3,3,2,4,1]

Example 3:

Input: nums = [1,1,2,2], n = 2 Output: [1,2,1,2]

 

Constraints:

• 1 <= n <= 500
• nums.length == 2n
• 1 <= nums[i] <= 10^3

 

class Solution:
    def shuffle(self, nums: List[int], n: int) -> List[int]:
        stack = [] 
        for i in range(n):
            stack.append(i)
            stack.append(i+n)

        stack02 = []
        for j in stack:
            stack02.append(nums[j])
    
        return stack02

# idea 

index 번호가 바뀌는 패턴을 이용하였다. 

n =3 일 때, 123456 => 142536

i 뒤에는 i +n 이 오게된다.  

 

# other way 

def shuffle(self, nums: List[int], n: int) -> List[int]:
        res = []
        for i, j in zip(nums[:n],nums[n:]):
            res += [i,j]
        return res