Final Value of Variable After Performing Operations

Problem Description

There is a programming language with only four operations and one variable X:

• ++X and X++ increment the value of the variable X by 1.
• --X and X-- decrement 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.

Examples

Example 1:

Input: operations = ["--X","X++","X++"]
Output: 1
Explanation: The operations are performed as follows:
Initially, X = 0.
--X: X is decremented by 1, X = 0 - 1 = -1.
X++: X is incremented by 1, X = -1 + 1 = 0.
X++: X is incremented by 1, X = 0 + 1 = 1.

Example 2:

Input: operations = ["++X","++X","X++"]
Output: 3
Explanation: The operations are performed as follows:
Initially, X = 0.
++X: X is incremented by 1, X = 0 + 1 = 1.
++X: X is incremented by 1, X = 1 + 1 = 2.
X++: X is incremented by 1, X = 2 + 1 = 3.

Example 3:

Input: operations = ["X++","++X","--X","X--"]
Output: 0
Explanation: The operations are performed as follows:
Initially, X = 0.
X++: X is incremented by 1, X = 0 + 1 = 1.
++X: X is incremented by 1, X = 1 + 1 = 2.
--X: X is decremented by 1, X = 2 - 1 = 1.
X--: X is decremented by 1, X = 1 - 1 = 0.

Constraints

• 1 <= operations.length <= 100
• operations[i] will be either "++X", "X++", "--X", or "X--".

Approach

To solve this problem, we will:

1. Initialize X to 0.
2. Iterate through each operation in the operations array.
3. Depending on the operation, increment or decrement X.
4. Return the final value of X.

C++

class Solution {
public:
    int finalValueAfterOperations(std::vector<std::string>& operations) {
        int X = 0;
        for (const auto& operation : operations) {
            if (operation == "++X" || operation == "X++") {
                X += 1;
            } else {
                X -= 1;
            }
        }
        return X;
    }
};

Python

def finalValueAfterOperations(operations):
    X = 0
    for operation in operations:
        if operation == "++X" or operation == "X++":
            X += 1
        else:
            X -= 1
    return X