Algorithm
Problem Name: 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 of
'+'.- 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 <= 1000operations[i]is"C","D","+", or a string representing an integer in the range[-3 * 104, 3 * 104].- 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.
Code Examples
#1 Code Example with Java Programming
Code -
Java Programming
class Solution {
public int calPoints(String[] ops) {
Stack stack = new Stack<>();
int totalScore = 0;
for (String op : ops) {
if (op.equals("D")) {
int newScore = 2 * stack.peek();
totalScore += newScore;
stack.push(newScore);
} else if (op.equals("C")) {
totalScore -= stack.pop();
} else if (op.equals("+")) {
int scoreTwo = stack.pop();
int newScore = scoreTwo + stack.peek();
stack.push(scoreTwo);
stack.push(newScore);
totalScore += newScore;
} else {
stack.push(Integer.parseInt(op));
totalScore += Integer.parseInt(op);
}
}
return totalScore;
}
}
Input
ops = ["5","2","C","D","+"]
Output
30
#2 Code Example with Javascript Programming
Code -
Javascript Programming
const calPoints = function(ops) {
const opArr = ["C", "D", "+"];
const arr = [];
ops.forEach((el, idx) => {
const item = {
value: 0,
valid: true
};
switch (el) {
case "C":
findValid(arr, idx, 1).forEach(el => {
el.value = 0;
el.valid = false;
});
item.valid = false;
break;
case "D":
item.value = findValid(arr, idx, 1)[0].value * 2;
break;
case "+":
item.value = findValid(arr, idx, 2).reduce(
(ac, ele) => ac + ele.value,
0
);
break;
default:
item.value = +el;
break;
}
arr.push(item);
});
return arr.reduce((ac, el) => ac + el.value, 0);
};
function findValid(arr, idx, backStep) {
const res = [];
while (backStep > 0 && idx - 1 >= 0) {
if (arr[idx - 1].valid === true) {
backStep -= 1;
res.push(arr[idx - 1]);
}
idx -= 1;
}
return res;
}
console.log(calPoints(["5", "2", "C", "D", "+"]));
console.log(calPoints(["5", "-2", "4", "C", "D", "9", "+", "+"]));
Input
ops = ["5","2","C","D","+"]
Output
30
#3 Code Example with Python Programming
Code -
Python Programming
class Solution:
def calPoints(self, ops: List[str]) -> int:
arr = []
for op in ops:
#print(arr)
if op.isdigit() or op[0] == '-':
arr.append(int(op))
elif op == 'C' and arr:
arr.pop()
elif op == 'D' and arr:
arr.append(arr[-1] * 2)
elif len(arr) >= 2:
arr.append(arr[-1] + arr[-2])
#print(arr)
return sum(arr)
Input
ops = ["5","-2","4","C","D","9","+","+"]
Output
27
#4 Code Example with C# Programming
Code -
C# Programming
namespace LeetCode
{
public class _0682_BaseballGame
{
public int CalPoints(string[] ops)
{
var roundPoints = new int[ops.Length];
var index = 0;
foreach (var op in ops)
{
if (op == "C")
index--;
else if (op == "D")
{
roundPoints[index] = roundPoints[index - 1] * 2;
index++;
}
else if (op == "+")
{
roundPoints[index] = roundPoints[index - 1] + roundPoints[index - 2];
index++;
}
else
roundPoints[index++] = int.Parse(op);
}
var sum = 0;
for (int i = 0; i < index; i++)
sum += roundPoints[i];
return sum;
}
}
}
Input
ops = ["5","-2","4","C","D","9","+","+"]
Output
27