> ## Documentation Index
> Fetch the complete documentation index at: https://leetcode-py.wisl.dev/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> leetcode-py is a Python LeetCode practice environment generator with one CLI: lcpy. It is not a service or platform.
> Each problem is a directory under leetcode/ with README.md, solution.py, test_solution.py, helpers.py, and playground.ipynb. lcpy gen creates them from JSON templates bundled with the package.
> Examples are backed by tests; copy them verbatim.

# Baseball Game Python Solution with Tests

> Tested Python solution for LeetCode 682 with 14 pytest cases. Generate a practice environment with lcpy.

LeetCode 682, Easy. Topics: Array, Stack, Simulation. [View on LeetCode](https://leetcode.com/problems/baseball-game/description/).

Generate this problem as a practice environment: tested reference solution, 14 [parametrized pytest cases](/practice/testing), and a playground notebook:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
lcpy gen -n 682   # by problem number
lcpy gen -s baseball_game   # by problem name
```

## 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.

You are given a list of strings `operations`, where `operations[i]` is the `ith` operation you must apply to the record and is one of the following:

* An integer `x`.
  * Record a new score of `x`.
* `'+'`.
  * Record a new score that is the sum of the previous two scores.
* `'D'`.
  * Record a new score that is the double of the previous score.
* `'C'`.
  * Invalidate the previous score, removing it from the record.

Return the sum of all the scores on the record after applying all the operations.

The test cases are generated such that the answer and all intermediate calculations fit in a **32-bit** integer and that all operations are valid.

### Examples

```
Input: ops = ["5","2","C","D","+"]
Output: 30
Explanation:
"5" - Add 5 to the record, record is now [5].
"2" - Add 2 to the record, record is now [5, 2].
"C" - Invalidate and remove the previous score, record is now [5].
"D" - Add 2 * 5 = 10 to the record, record is now [5, 10].
"+" - Add 5 + 10 = 15 to the record, record is now [5, 10, 15].
The total sum is 5 + 10 + 15 = 30.
```

```
Input: ops = ["5","-2","4","C","D","9","+","+"]
Output: 27
```

```
Input: ops = ["1","C"]
Output: 0
```

### Constraints

* 1 \<= operations.length \<= 1000
* `operations[i]` is `"C"`, `"D"`, `"+"`, or a string representing an integer in the range \[-3 \* 10^4, 3 \* 10^4].
* For operation `"+"`, there will always be at least two previous scores on the record.
* For operations `"C"` and `"D"`, there will always be at least one previous score on the record.

## Solution

Reference implementation from [solution.py on GitHub](https://github.com/wislertt/leetcode-py/blob/main/leetcode/baseball_game/solution.py), full suite in [test\_solution.py](https://github.com/wislertt/leetcode-py/blob/main/leetcode/baseball_game/test_solution.py):

```python theme={"theme":{"light":"github-light","dark":"github-dark"}}
class Solution:
    # Time: O(n)
    # Space: O(n)
    def cal_points(self, operations: list[str]) -> int:
        record: list[int] = []
        for op in operations:
            if op == "+":
                record.append(record[-1] + record[-2])
            elif op == "D":
                record.append(2 * record[-1])
            elif op == "C":
                record.pop()
            else:
                record.append(int(op))
        return sum(record)
```

## Complexity

| Time | Space |
| ---- | ----- |
| O(n) | O(n)  |

## Tags

[NeetCode 250](/catalog/neetcode-250), [NeetCode All](/catalog/neetcode).