682.baseball-game.js

/*
 * @lc app=leetcode id=682 lang=javascript
 *
 * [682] Baseball Game
 *
 * https://leetcode.com/problems/baseball-game/description/
 *
 * algorithms
 * Easy (61.70%)
 * Likes:    345
 * Dislikes: 854
 * Total Accepted:    60.5K
 * Total Submissions: 98.1K
 * Testcase Example:  '["5","2","C","D","+"]'
 *
 * 
 * You're now a baseball game point recorder.
 * 
 * 
 * 
 * Given a list of strings, each string can be one of the 4 following types:
 * 
 * Integer (one round's score): Directly represents the number of points you
 * get in this round.
 * "+" (one round's score): Represents that the points you get in this round
 * are the sum of the last two valid round's points.
 * "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.
 * "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.
 * 
 */

// @lc code=start
/**
 * @param {string[]} ops
 * @return {number}
 */
var calPoints = function (ops) {
    return ops.reduce((acc, crr) => {
        switch (crr) {
            case '+':
                acc.push(acc[acc.length - 1] + acc[acc.length - 2]);
                break;
            case 'D':
                acc.push(acc[acc.length - 1] * 2);
                break;
            case 'C':
                acc.pop();
                break;
            default:
                acc.push(Number(crr));
                break;
        }
        return acc;
    }, []).reduce((a, b) => a + b, 0);
};
// @lc code=end