QUESTION:
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--".
EXPLANATION:
很简单, 没有特别想说的.
SOLUTION:
class Solution {
func finalValueAfterOperations(_ operations: [String]) -> Int {
var result:Int = 0
for operation in operations {
if((operation == "X++") || (operation == "++X")) {
result+=1
} else if ((operation == "X--") || (operation == "--X")) {
result-=1
}
}
return result
}
}