题目
Given an array target and an integer n. In each iteration, you will read a number from list = {1,2,3…, n}.
Build the target array using the following 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.
You are guaranteed that the target array is strictly increasing, only containing numbers between 1 to n inclusive.
Return the operations to build the target array.
You are guaranteed that the answer is unique.
解题思路
遍历1到n中的每个数，如果这个数在target中出现，就加一个Push,否则加一个Push和Pop，如果target数组已经遍历完了，就退出循环
代码
class Solution:
def buildArray(self, target, n: int):
res = []
p = 0
for i in range(1, n + 1):
if target[p] == i:
res.append("Push")
p += 1
else:
res.append("Push")
res.append("Pop")
if p == len(target):
break
return res
