20_Final_Value_of_Variable_After_Performing_Operations.cpp

// 2011. Final Value of Variable After Performing Operations

// 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--".

class Solution
{
public:
    int finalValueAfterOperations(vector<string> &operations)
    {
        int x = 0;
        for (auto &op : operations)
            x += (op[1] == '+') ? 1 : -1;
        return x;
    }
};