algorithms/leetcode/682-BaseballGame.go at master · freewu/algorithms · GitHub

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package main

// 682. Baseball Game
// 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.

// Example 1:
// 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.

// Example 2:
// Input: ops = ["5","-2","4","C","D","9","+","+"]
// Output: 27
// Explanation:
// "5" - Add 5 to the record, record is now [5].
// "-2" - Add -2 to the record, record is now [5, -2].
// "4" - Add 4 to the record, record is now [5, -2, 4].
// "C" - Invalidate and remove the previous score, record is now [5, -2].
// "D" - Add 2 * -2 = -4 to the record, record is now [5, -2, -4].
// "9" - Add 9 to the record, record is now [5, -2, -4, 9].
// "+" - Add -4 + 9 = 5 to the record, record is now [5, -2, -4, 9, 5].
// "+" - Add 9 + 5 = 14 to the record, record is now [5, -2, -4, 9, 5, 14].
// The total sum is 5 + -2 + -4 + 9 + 5 + 14 = 27.

// Example 3:
// Input: ops = ["1","C"]
// Output: 0
// Explanation:
// "1" - Add 1 to the record, record is now [1].
// "C" - Invalidate and remove the previous score, record is now [].
// Since the record is empty, the total sum is 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.

import "fmt"
import "strconv"

func calPoints(operations []string) int {
    r := []int{}
    for _, v := range operations {
        if v == "C" { // r 最后一位出栈
            r = r[:len(r) - 1]
        } else if v == "D" { // 最后一位 * 2
            r = append(r,r[len(r) - 1] * 2)
        } else if v == "+" {
            r = append(r,r[len(r) - 1]  + r[len(r) - 2])
        } else {
            a, _ := strconv.Atoi(v)
            r = append(r, a)
        }
    }
    // 累加 r
    res := 0
    for _,v := range r {
        res += v
    }
    return res
}

func main() {
    // "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.
    fmt.Println(calPoints([]string{"5","2","C","D","+"})) // 30

    // "5" - Add 5 to the record, record is now [5].
    // "-2" - Add -2 to the record, record is now [5, -2].
    // "4" - Add 4 to the record, record is now [5, -2, 4].
    // "C" - Invalidate and remove the previous score, record is now [5, -2].
    // "D" - Add 2 * -2 = -4 to the record, record is now [5, -2, -4].
    // "9" - Add 9 to the record, record is now [5, -2, -4, 9].
    // "+" - Add -4 + 9 = 5 to the record, record is now [5, -2, -4, 9, 5].
    // "+" - Add 9 + 5 = 14 to the record, record is now [5, -2, -4, 9, 5, 14].
    // The total sum is 5 + -2 + -4 + 9 + 5 + 14 = 27.
    fmt.Println(calPoints([]string{"5","-2","4","C","D","9","+","+"})) // 27

    // "1" - Add 1 to the record, record is now [1].
    // "C" - Invalidate and remove the previous score, record is now [].
    // Since the record is empty, the total sum is 0.// I
    fmt.Println(calPoints([]string{"1","C"})) // 0
}