You are given an integer array target and an integer n.
You have an empty stack with the two following operations:
\n\n"Push": pushes an integer to the top of the stack."Pop": removes the integer on the top of the stack.You also have a stream of the integers in the range [1, n].
Use the two stack operations to make the numbers in the stack (from the bottom to the top) equal to target. You should follow the following rules:
target, do not read new integers from the stream and do not do more operations on the stack.Return the stack operations needed to build target following the mentioned rules. If there are multiple valid answers, return any of them.
\n
Example 1:
\n\n\nInput: target = [1,3], n = 3\nOutput: ["Push","Push","Pop","Push"]\nExplanation: Initially the stack s is empty. The last element is the top of the stack.\nRead 1 from the stream and push it to the stack. s = [1].\nRead 2 from the stream and push it to the stack. s = [1,2].\nPop the integer on the top of the stack. s = [1].\nRead 3 from the stream and push it to the stack. s = [1,3].\n\n\n
Example 2:
\n\n\nInput: target = [1,2,3], n = 3\nOutput: ["Push","Push","Push"]\nExplanation: Initially the stack s is empty. The last element is the top of the stack.\nRead 1 from the stream and push it to the stack. s = [1].\nRead 2 from the stream and push it to the stack. s = [1,2].\nRead 3 from the stream and push it to the stack. s = [1,2,3].\n\n\n
Example 3:
\n\n\nInput: target = [1,2], n = 4\nOutput: ["Push","Push"]\nExplanation: Initially the stack s is empty. The last element is the top of the stack.\nRead 1 from the stream and push it to the stack. s = [1].\nRead 2 from the stream and push it to the stack. s = [1,2].\nSince the stack (from the bottom to the top) is equal to target, we stop the stack operations.\nThe answers that read integer 3 from the stream are not accepted.\n\n\n
\n
Constraints:
\n\n1 <= target.length <= 1001 <= n <= 1001 <= target[i] <= ntarget is strictly increasing.Compiled with clang 11 using the latest C++ 20 standard.
Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.
Most standard library headers are already included automatically for your convenience.
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