Baseball Game — LeetCode 682 Python Solution

The problem

You are keeping the scores for a baseball game with strange rules. At the beginning of the game, you start with an empty record.

Example

Input

ops = ["5","2","C","D","+"]

Output

30

Explanation

"5" - Add 5 to the record, record is now [5].

Python solution

class Solution:
    def calPoints(self, operations: List[str]) -> int:
        stk = []
        for op in operations:
            if op == "+":
                stk.append(stk[-1] + stk[-2])
            elif op == "D":
                stk.append(stk[-1] << 1)
            elif op == "C":
                stk.pop()
            else:
                stk.append(int(op))
        return sum(stk)

Complexity

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 682. Baseball Game is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Stack.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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