[Swift] Reverse Integer
Reverse digits of an integer.
Example1: x = 123, return 321
Example2: x = -123, return -321
Example2: x = -123, return -321
//Way1 用mod取餘數去解
func reverse2(_ x: Int) -> Int {
var y = x
var returnVal = 0
while (y != 0){
returnVal = 10*returnVal + y%10
y = y / 10
}
if (returnVal>Int.max || returnVal<Int.min) {
return 0
}else{
return returnVal
}
}
//Way2 用string去解
func reverse(_ x: Int) -> Int {
if x > Int.max || x < Int.min || x == 0 { return 0 }
var returnVal = x
var isNagative:Bool = false
if x < 0 {
isNagative = true
returnVal = abs(x)
}
let myString = String(String(returnVal).characters.reversed())
if Int(myString) != nil {
if isNagative == true {
return 0-Int(myString)!
}else{
return Int(myString)!
}
}else{
return 0
}
}
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