value_of_variale.py

# 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--".
def finalValueAfterOperations(operations):
    x = 0
    ops = {"++X": 1, "X++": 1, "--X": -1, "X--": -1}
    for operation in operations:
        x += ops[operation]
    return x