2011-final-value-of-variable-after-performing-operations.js

/**
 * 2011. Final Value of Variable After Performing Operations
 * https://leetcode.com/problems/final-value-of-variable-after-performing-operations/
 * Difficulty: Easy
 *
 * There is a programming language with only four operations and one variable X:
 * - ++X and X++ increments the value of the variable X by 1.
 * - --X and X-- decrements the value of the variable X by 1.
 *
 * Initially, the value of X is 0.
 *
 * Given an array of strings operations containing a list of operations, return the
 * final value of X after performing all the operations.
 */

/**
 * @param {string[]} operations
 * @return {number}
 */
var finalValueAfterOperations = function(operations) {
  return operations
    .map(n => n.includes('++') ? 1 : -1)
    .reduce((sum, n) => sum + n, 0);
};