Add solution #682

Author: JoshCrozier

README.md

@@ -514,6 +514,7 @@
 678|[Valid Parenthesis String](./0678-valid-parenthesis-string.js)|Medium|
 679|[24 Game](./0679-24-game.js)|Hard|
 680|[Valid Palindrome II](./0680-valid-palindrome-ii.js)|Easy|
+682|[Baseball Game](./0682-baseball-game.js)|Easy|
 684|[Redundant Connection](./0684-redundant-connection.js)|Medium|
 686|[Repeated String Match](./0686-repeated-string-match.js)|Easy|
 693|[Binary Number with Alternating Bits](./0693-binary-number-with-alternating-bits.js)|Easy|

solutions/0682-baseball-game.js

@@ -0,0 +1,41 @@
+/**
+ * 682. Baseball Game
+ * https://leetcode.com/problems/baseball-game/
+ * Difficulty: Easy
+ *
+ * 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.
+ */
+
+/**
+ * @param {string[]} ops
+ * @return {number}
+ */
+var calPoints = function(ops) {
+  const stack = [];
+
+  for (const op of ops) {
+    if (op === 'C') stack.pop();
+    else if (op === 'D') stack.push(stack.at(-1) * 2);
+    else if (op === '+') stack.push(stack.at(-1) + stack.at(-2));
+    else stack.push(Number(op));
+  }
+
+  return stack.reduce((sum, num) => sum + num, 0);
+};