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| 1 | +/** |
| 2 | + |
| 3 | +You're now a baseball game point recorder. |
| 4 | + |
| 5 | +Given a list of strings, each string can be one of the 4 following types: |
| 6 | + |
| 7 | +Integer (one round's score): Directly represents the number of points you get in this round. |
| 8 | +"+" (one round's score): Represents that the points you get in this round are the sum of the last two valid round's points. |
| 9 | +"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. |
| 10 | +"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. |
| 11 | +Each round's operation is permanent and could have an impact on the round before and the round after. |
| 12 | + |
| 13 | +You need to return the sum of the points you could get in all the rounds. |
| 14 | + |
| 15 | +*/ |
| 16 | + |
| 17 | +const Stack = require('../index'); |
| 18 | + |
| 19 | +// The given solution is on O(n) |
| 20 | + |
| 21 | +function sumOfPoints(arr) { |
| 22 | + const pointsTracker = new Stack(); |
| 23 | + let sum = 0; |
| 24 | + |
| 25 | + if (!Array.isArray(arr)) { |
| 26 | + throw new Error('Invalid Argument!'); |
| 27 | + } |
| 28 | + // Track the value of `sum` accordingly |
| 29 | + for (let el of arr) { |
| 30 | + // console.log('data : ', pointsTracker.data); |
| 31 | + // console.log('sum : ', sum); |
| 32 | + |
| 33 | + if (el === 'C') { |
| 34 | + // pop if the value is `C` |
| 35 | + const top = pointsTracker.pop(); |
| 36 | + if (top) { |
| 37 | + sum -= top; |
| 38 | + } |
| 39 | + } else if (el === 'D') { |
| 40 | + // Double the top id the value is 'D' |
| 41 | + const top = pointsTracker.peek(); |
| 42 | + sum += top * 2; |
| 43 | + pointsTracker.push(top * 2); |
| 44 | + } else if (el === '+') { |
| 45 | + const top = pointsTracker.pop(); |
| 46 | + const secondTop = pointsTracker.peek(); |
| 47 | + |
| 48 | + const result = top + secondTop; |
| 49 | + sum += result; |
| 50 | + |
| 51 | + pointsTracker.push(top); |
| 52 | + pointsTracker.push(result); |
| 53 | + } else { |
| 54 | + // push to the Stack if the value is integer |
| 55 | + sum += parseInt(el); |
| 56 | + pointsTracker.push(parseInt(el)); |
| 57 | + } |
| 58 | + } |
| 59 | + return sum; |
| 60 | +} |
| 61 | + |
| 62 | +/** |
| 63 | + * Let's Try it out |
| 64 | + |
| 65 | +console.log(sumOfPoints(['5', '2', 'C', 'D', '+'])); |
| 66 | +console.log(sumOfPoints(['5', '-2', '4', 'C', 'D', '9', '+', '+'])); |
| 67 | + */ |
| 68 | + |
| 69 | +/** |
| 70 | + |
| 71 | +Input: ["5","2","C","D","+"] |
| 72 | +Output: 30 |
| 73 | + |
| 74 | +Explanation: |
| 75 | + |
| 76 | +Round 1: You could get 5 points. The sum is: 5. |
| 77 | +Round 2: You could get 2 points. The sum is: 7. |
| 78 | +Operation 1: The round 2's data was invalid. The sum is: 5. |
| 79 | +Round 3: You could get 10 points (the round 2's data has been removed). The sum is: 15. |
| 80 | +Round 4: You could get 5 + 10 = 15 points. The sum is: 30. |
| 81 | +Example 2: |
| 82 | +Input: ["5","-2","4","C","D","9","+","+"] |
| 83 | +Output: 27 |
| 84 | + |
| 85 | +Explanation: |
| 86 | + |
| 87 | +Round 1: You could get 5 points. The sum is: 5. |
| 88 | +Round 2: You could get -2 points. The sum is: 3. |
| 89 | +Round 3: You could get 4 points. The sum is: 7. |
| 90 | +Operation 1: The round 3's data is invalid. The sum is: 3. |
| 91 | +Round 4: You could get -4 points (the round 3's data has been removed). The sum is: -1. |
| 92 | +Round 5: You could get 9 points. The sum is: 8. |
| 93 | +Round 6: You could get -4 + 9 = 5 points. The sum is 13. |
| 94 | +Round 7: You could get 9 + 5 = 14 points. The sum is 27. |
| 95 | + |
| 96 | +Note: |
| 97 | + |
| 98 | +The size of the input list will be between 1 and 1000. |
| 99 | +Every integer represented in the list will be between -30000 and 30000. |
| 100 | + |
| 101 | +*/ |
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