2011-FinalValueOfVariableAfterPerformingOperations.go

package main

// 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--".

import "fmt"

func finalValueAfterOperations(operations []string) int {
    res := 0
    for _, v := range operations {
        if v[1] == '+' {
            res++
        } else { // -
            res--
        }
    }
    return res
}

func main() {
    // 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.
    fmt.Println(finalValueAfterOperations([]string{"--X","X++","X++"})) // 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.
    fmt.Println(finalValueAfterOperations([]string{"++X","++X","X++"})) // 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.
    fmt.Println(finalValueAfterOperations([]string{"X++","++X","--X","X--"})) // 0
}