[Swift]LeetCode682. 棒球比賽 | Baseball Game

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You're now a baseball game point recorder.

Given a list of strings, each string can be one of the 4 following types:

1. Integer (one round's score): Directly represents the number of points you get in this round.
2. "+" (one round's score): Represents that the points you get in this round are the sum of the last two validround's points.
3. "D" (one round's score): Represents that the points you get in this round are the doubled data of the last valid round's points.
4. "C" (an operation, which isn't a round's score): Represents the last valid round's points you get were invalid and should be removed. 

Each round's operation is permanent and could have an impact on the round before and the round after.

You need to return the sum of the points you could get in all the rounds.

Example 1:

Input: ["5","2","C","D","+"]
Output: 30
Explanation: 
Round 1: You could get 5 points. The sum is: 5.
Round 2: You could get 2 points. The sum is: 7.
Operation 1: The round 2's data was invalid. The sum is: 5.  
Round 3: You could get 10 points (the round 2's data has been removed). The sum is: 15.
Round 4: You could get 5 + 10 = 15 points. The sum is: 30. 

Example 2:

Input: ["5","-2","4","C","D","9","+","+"]
Output: 27
Explanation: 
Round 1: You could get 5 points. The sum is: 5.
Round 2: You could get -2 points. The sum is: 3.
Round 3: You could get 4 points. The sum is: 7.
Operation 1: The round 3's data is invalid. The sum is: 3.  
Round 4: You could get -4 points (the round 3's data has been removed). The sum is: -1.
Round 5: You could get 9 points. The sum is: 8.
Round 6: You could get -4 + 9 = 5 points. The sum is 13.
Round 7: You could get 9 + 5 = 14 points. The sum is 27. 

Note:

• The size of the input list will be between 1 and 1000.
• Every integer represented in the list will be between -30000 and 30000.

---

你如今是棒球比賽記錄員。
給定一個字符串列表，每一個字符串能夠是如下四種類型之一：
1.整數（一輪的得分）：直接表示您在本輪中得到的積分數。
2. "+"（一輪的得分）：表示本輪得到的得分是前兩輪有效 回合得分的總和。
3. "D"（一輪的得分）：表示本輪得到的得分是前一輪有效 回合得分的兩倍。
4. "C"（一個操做，這不是一個回合的分數）：表示您得到的最後一個有效 回合的分數是無效的，應該被移除。

每一輪的操做都是永久性的，可能會對前一輪和後一輪產生影響。
你須要返回你在全部回合中得分的總和。

示例 1:

輸入: ["5","2","C","D","+"]
輸出: 30
解釋: 
第1輪：你能夠獲得5分。總和是：5。
第2輪：你能夠獲得2分。總和是：7。
操做1：第2輪的數據無效。總和是：5。
第3輪：你能夠獲得10分（第2輪的數據已被刪除）。總數是：15。
第4輪：你能夠獲得5 + 10 = 15分。總數是：30。

示例 2:

輸入: ["5","-2","4","C","D","9","+","+"]
輸出: 27
解釋: 
第1輪：你能夠獲得5分。總和是：5。
第2輪：你能夠獲得-2分。總數是：3。
第3輪：你能夠獲得4分。總和是：7。
操做1：第3輪的數據無效。總數是：3。
第4輪：你能夠獲得-4分（第三輪的數據已被刪除）。總和是：-1。
第5輪：你能夠獲得9分。總數是：8。
第6輪：你能夠獲得-4 + 9 = 5分。總數是13。
第7輪：你能夠獲得9 + 5 = 14分。總數是27。

注意：

• 輸入列表的大小將介於1和1000之間。
• 列表中的每一個整數都將介於-30000和30000之間。

---

Runtime: 28 ms

Memory Usage: 20.1 MB

 1 class Solution {
 2     func calPoints(_ ops: [String]) -> Int {
 3         var v:[Int] = [Int]()
 4         for op in ops
 5         {
 6             if op == "+"
 7             {
 8                 v.append(v.last! + v[v.count - 2])
 9             }
10             else if op == "D"
11             {
12                 v.append(2 * v.last!)
13             }
14             else if op == "C"
15             {
16                 v.popLast()
17             }
18             else
19             {
20                 v.append(Int(op)!)                
21             }           
22         }
23         return v.reduce(0,+)
24     }
25 }

---

28ms

 1 class Solution {
 2     func calPoints(_ ops: [String]) -> Int {
 3         var points:Int = 0
 4         var poStack:[Int] = []
 5         
 6         for i in 0..<ops.count {
 7             if ops[i] == "+" {
 8                 let n:Int = poStack.count - 2
 9                 points = points + poStack[n] + poStack.last!
10                 poStack.append(poStack[n] + poStack.last!)
11                 
12             }else if ops[i] == "C"{
13                 let temp:Int = poStack.last!
14                 poStack.removeLast()
15                 points = points - temp
16                 
17             }else if ops[i] == "D" {
18                 points = points + poStack.last! * 2
19                 let po = poStack.last! * 2
20                 poStack.append(po)
21                 
22             }else{
23                 points = points + Int(ops[i])!
24                 poStack.append(Int(ops[i])!)
25             }
26         }
27         
28         return points
29     }
30 }

---

32ms

 1 class Solution {
 2     func calPoints(_ ops: [String]) -> Int {
 3         var stack = [Int]()
 4         var sum = 0
 5         for ch in ops {
 6             switch ch {
 7             case "C":
 8                 let x = stack.removeLast()
 9                 sum -= x
10             case "D":
11                 if let x = stack.last {
12                     stack.append(x * 2)
13                     sum += x * 2
14                 }
15             case "+":
16                 if stack.count >= 2 {
17                     let x = stack[stack.count - 1]
18                     let y = stack[stack.count - 2]
19                     stack.append(x + y)
20                     sum += (x + y)
21                 }
22             default:
23                 if let x = Int(ch) {
24                     stack.append(x)
25                     sum += x
26                 }
27             }
28         }
29         return sum
30     }
31 }

---

36ms

 1 class Solution {
 2     func calPoints(_ ops: [String]) -> Int {
 3         var stack = [String]()
 4         for op in ops {
 5             if Int(op) != nil {
 6                 stack.append(op)
 7             } else if op == "C" && stack.count > 0 {
 8                 stack.removeLast()
 9             } else if op == "D" && stack.count > 0 {
10                 stack.append(String(Int(stack.last!)! * 2))
11             } else if stack.count >= 2 {
12                 let sum = String(Int(stack.last!)! + Int(stack[stack.count - 2])!)
13                 stack.append(sum)
14             }
15         }
16         
17         var ans = 0
18         for item in stack {
19             ans += Int(item)!
20         }
21         return ans
22     }
23 }

---

40ms

 1 struct Stack<T: Equatable> {
 2   private var list: [T]
 3   init() {
 4     list = [T]()
 5   }
 6   var isEmpty:Bool {
 7     return list.count == 0
 8   }
 9   var count: Int {
10     return list.count
11   }
12   mutating func push(_ value: T) {
13     list.append(value)
14   }
15   
16   mutating func pop() -> T? {
17     guard !isEmpty else { return nil }
18     return list.removeLast()
19   }
20   
21   func peek() -> T? {
22     return list.last
23   }
24   func peekLastButOne() -> T? {
25     guard !isEmpty else { return nil }
26     guard count > 1 else { return nil }
27     return list[count-2]
28   }
29 }
30 
31 class Solution {
32     func calPoints(_ ops: [String]) -> Int {
33         var dataStack = Stack<Int>()
34         var totalSum = 0
35         for element in ops {
36             if let number = Int(element) { 
37                 // handle integers
38                 dataStack.push(number)
39                 totalSum += number
40             }
41             else {
42                 if element == "C" {
43                     // cancel case operation
44                     let val = dataStack.pop() ?? 0
45                     totalSum -= val
46                 } else if element == "D" {
47                     // double round
48                     var val = dataStack.peek() ?? 0
49                     val *= 2
50                     dataStack.push(val)
51                     totalSum += val
52                 } else {
53                     var val1 = dataStack.peek() ?? 0
54                     let val2 = dataStack.peekLastButOne() ?? 0
55                     val1 += val2
56                     dataStack.push(val1)
57                     totalSum += val1
58                     // sum of last 2 rounds results
59                 }
60             }
61         }
62         return totalSum
63     }
64 }

---

60ms

 1 class Solution {
 2     func calPoints(_ ops: [String]) -> Int {
 3         var history = [Int]()
 4         for op in ops {
 5             if op == "+" {
 6                 history.append(history[history.count-1] + history[history.count-2])
 7             } else if op == "D" {
 8                 history.append(history[history.count-1] * 2)
 9             } else if op == "C" {
10                 history.removeLast()
11             } else {
12                 history.append(Int(op)!)
13             }
14         }
15 
16         return history.reduce(0) { $0 + $1 }
17     }
18 }

---

76ms

 1 class Solution {
 2     func calPoints(_ ops: [String]) -> Int {
 3             if ops.count < 1 {
 4                 return 0
 5             }
 6             var result = 0
 7             var statckArray : [Int] = []
 8             var temp = 0
 9             for score in ops {
10                 if score == "C" && statckArray.count > 0{
11                     statckArray.removeLast()
12                 }else if score == "D" && statckArray.count > 0 {
13                     temp = statckArray.last!
14                     statckArray.append(temp*2)
15                 }else if score == "+" && statckArray.count > 1 {
16                     temp = statckArray.last! + statckArray[statckArray.count-2]
17                     statckArray.append(temp)
18                 }else if score == "+" && statckArray.count == 1 {
19                     temp = statckArray.last!
20                     statckArray.append(temp)
21                 }else if isPurnInt(string: score) {
22                     statckArray.append(Int(score)!)
23                 }
24             }
25             while statckArray.count > 0 {
26                 result = result + statckArray.last!
27                 statckArray.removeLast()
28             }
29             return result
30         }
31         func isPurnInt(string: String) -> Bool {
32             let scan: Scanner = Scanner(string: string)
33             var val:Int = 0
34             return scan.scanInt(&val) && scan.isAtEnd
35             
36         }
37 }