LeetCode Challenge Day 35 — 2011. Final Value of Variable After Performing Operations

Hey folks

This is Day 35 of my LeetCode streak 🚀.
Today’s problem is 2011. Final Value of Variable After Performing Operations — a simple simulation problem where we execute increment/decrement operations and track the final result of a variable.

📌 Problem Statement

You are given an array of strings operations, where each string is one of:

• "--X", "X--" → decrement by 1
• "++X", "X++" → increment by 1

Return the final value of variable X after performing all operations.

💡 Intuition

The operations are straightforward — each one either increases or decreases X by 1.
We can simply simulate the process:

• Start with X = 0.
• For each operation, check if it contains "++" → increment, else decrement.

🔑 Approach

1. Initialize X = 0.
2. Loop through all operations.
   • If the operation string contains "++", do X++.
   • Otherwise, do X--.
3. Return the final value of X.

⏱️ Complexity Analysis

• Time complexity:
  Each operation is processed in O(1). For n operations → O(n).

• Space complexity:
  Only a constant amount of memory is used → O(1).

🧑‍💻 Code (JavaScript)

/**
 * @param {string[]} operations
 * @return {number}
 */
var finalValueAfterOperations = function(operations) {
    let X = 0;
    for (let op of operations) {
        if (op.includes("++")) {
            X++;
        } else {
            X--;
        }
    }
    return X;
};

🧪 Example Walkthrough

Input: operations = ["--X","X++","X++"]

Start: X = 0

"--X" → decrement → X = -1

"X++" → increment → X = 0

"X++" → increment → X = 1

Output: 1

🎥 Reflections

This problem is a nice reminder that not every LeetCode challenge needs advanced data structures or algorithms — sometimes a clean, simple simulation does the trick.

That’s it for Day 35 of my LeetCode journey! Onwards to the next challenge 🔥

Happy Coding 👨‍💻