2011. Final Value of Variable After Performing Operations

https://leetcode.com/problems/final-value-of-variable-after-performing-operations

Description

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.

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--".

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