[Leet Code] Build an Array With Stack Operations

  • Push: Read a new element from the beginning list, and push it in the array.
  • Pop: delete the last element of the array.
  • If the target array is already built, stop reading more elements.
Input: target = [1,3], n = 3
Output: ["Push","Push","Pop","Push"]
Explanation:
Read number 1 and automatically push in the array -> [1]
Read number 2 and automatically push in the array then Pop it -> [1]
Read number 3 and automatically push in the array -> [1,3]
Input: target = [1,2,3], n = 3
Output: ["Push","Push","Push"]
Input: target = [1,2], n = 4
Output: ["Push","Push"]
Explanation: You only need to read the first 2 numbers and stop.
Input: target = [2,3,4], n = 4
Output: ["Push","Pop","Push","Push","Push"]
  • 1 <= target.length <= 100
  • 1 <= target[i] <= n
  • 1 <= n <= 100
  • target is strictly increasing.
class Solution(object):
def buildArray(self, target, n):
"""
:type target: List[int]
:type n: int
:rtype: List[str]
"""
result_list = []
for i in range(1,n+1):
if i>target[len(target)-1]:
return result_list
result_list.append("Push")
if i not in target:
result_list.append("Pop")
return result_list

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Matthew Boyd

Matthew Boyd

Learning, and posting my findings!