52 lines
2.3 KiB
Markdown
52 lines
2.3 KiB
Markdown
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You are keeping score for a baseball game with strange rules. The game consists of several rounds, where the scores of past rounds may affect future rounds' scores.
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At the beginning of the game, you start with an empty record. You are given a list of strings `ops`, where `ops[i]` is the `ith` operation you must apply to the record and is one of the following:
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1. An integer `x` - Record a new score of `x`.
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2. `"+"` - Record a new score that is the sum of the previous two scores. It is guaranteed there will always be two previous scores.
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3. `"D"` - Record a new score that is double the previous score. It is guaranteed there will always be a previous score.
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4. `"C"` - Invalidate the previous score, removing it from the record. It is guaranteed there will always be a previous score.
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Return _the sum of all the scores on the record_.
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**Example 1:**
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Input: ops = ["5","2","C","D","+"]
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Output: 30
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Explanation:
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"5" - Add 5 to the record, record is now [5].
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"2" - Add 2 to the record, record is now [5, 2].
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"C" - Invalidate and remove the previous score, record is now [5].
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"D" - Add 2 * 5 = 10 to the record, record is now [5, 10].
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"+" - Add 5 + 10 = 15 to the record, record is now [5, 10, 15].
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The total sum is 5 + 10 + 15 = 30.
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**Example 2:**
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Input: ops = ["5","-2","4","C","D","9","+","+"]
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Output: 27
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Explanation:
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"5" - Add 5 to the record, record is now [5].
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"-2" - Add -2 to the record, record is now [5, -2].
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"4" - Add 4 to the record, record is now [5, -2, 4].
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"C" - Invalidate and remove the previous score, record is now [5, -2].
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"D" - Add 2 * -2 = -4 to the record, record is now [5, -2, -4].
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"9" - Add 9 to the record, record is now [5, -2, -4, 9].
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"+" - Add -4 + 9 = 5 to the record, record is now [5, -2, -4, 9, 5].
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"+" - Add 9 + 5 = 14 to the record, record is now [5, -2, -4, 9, 5, 14].
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The total sum is 5 + -2 + -4 + 9 + 5 + 14 = 27.
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**Example 3:**
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Input: ops = ["1"]
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Output: 1
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**Constraints:**
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* `1 <= ops.length <= 1000`
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* `ops[i]` is `"C"`, `"D"`, `"+"`, or a string representing an integer in the range `[-3 * 104, 3 * 104]`.
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* For operation `"+"`, there will always be at least two previous scores on the record.
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* For operations `"C"` and `"D"`, there will always be at least one previous score on the record.
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