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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.

Example 1:

Input: target = [1,3], n = 3
Output: ["Push","Push","Pop","Push"]
Explanation:
Read number 1 and automatically push in the array -> 
Read number 2 and automatically push in the array then Pop it -> 
Read number 3 and automatically push in the array -> [1,3]


Example 2:

Input: target = [1,2,3], n = 3
Output: ["Push","Push","Push"]


Example 3:

Input: target = [1,2], n = 4
Output: ["Push","Push"]
Explanation: You only need to read the first 2 numbers and stop.


Example 4:

Input: target = [2,3,4], n = 4
Output: ["Push","Pop","Push","Push","Push"]


Constraints:

• 1 <= target.length <= 100
• 1 <= target[i] <= 100
• 1 <= n <= 100
• target is strictly increasing.

## Solution: Simulation

For each number in target, keep discarding i if i != num by “Push” + “Pop”, until i == num. One more “Push”.

Time complexity: O(n)
Space complexity: O(n) or O(1) w/o output.

## C++

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