[Swift]LeetCode166. 分数到小数 | Fraction to Recurring Decimal

概述Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If the fractional part is repeating, enclose the repeating part in parentheses. Examp

Given two integers representing the numerator and denominator of a fraction,return the fraction in string format.

If the fractional part is repeating,enclose the repeating part in parentheses.

Example 1:

input: numerator = 1,denominator = 2Output: "0.5"

Example 2:

input: numerator = 2,denominator = 1Output: "2"

Example 3:

input: numerator = 2,denominator = 3Output: "0.(6)"

给定两个整数，分别表示分数的分子 numerator 和分母 denominator，以字符串形式返回小数。

如果小数部分为循环小数，则将循环的部分括在括号内。

示例 1:

输入: numerator = 1,denominator = 2输出: "0.5"

示例 2:

输入: numerator = 2,denominator = 1输出: "2"

示例 3:

输入: numerator = 2,denominator = 3输出: "0.(6)"

8ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3         let s1 = numerator > 0 ? 1 : -1 4         let s2 = denominator > 0 ? 1 : -1 5         let numerator = abs(numerator) 6         let denominator = abs(denominator) 7         let num = numerator / denominator 8         var remain = numerator % denominator  9         var remains = [Int : Int]()10         var res = ""11         if s1*s2 < 0 && (num > 0 || remain > 0) {12             res += "-"13         }14         res += "\(num)"15         if remain > 0 {16             res += "."17         }18         var frac = ""19         var pos = 020         while remain > 0 {21             if let pos = remains[remain] {22                 frac.insert("(",at: frac.index(frac.startIndex,offsetBy: pos))23                 frac += ")"24                 return res+frac25             }26             remains[remain] = pos27             frac += String(remain*10 / denominator)28             remain = remain*10 % denominator29             pos += 130         }31         return res+frac32     }33 }

12ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3          4         if denominator == 0 { return "NaN" } 5          6         //Big bad voodoo magic. 7         var numerator = numerator 8         var denominator = denominator 9         10         //Note,for bools "!=" behaves the same as "^" which is not allowed.11         var negative = (numerator < 0) != (denominator < 0)12         13         numerator = abs(numerator)14         denominator = abs(denominator)15         16         var result = String(numerator / denominator)17         var remainder = (numerator % denominator) * 1018         19         if remainder == 0 {20             if negative == true && numerator != 0 {21                 return String("-") + result22             } else {23                 return result24             }25         }26         27         result += "."28         29         //See if we find repeating digits...30         //At the point where our long division keeps31         //divIDing into the same NO,we loop 4evz32         var repeatMap = [Int:Int]()33         34         while remainder != 0 {35             36             //We got a repeater? Or nah?37             if let repeatIndex = repeatMap[remainder] {38                 result.insert("(",at: result.index(result.startIndex,offsetBy: repeatIndex))39                 result += ")"40                 break41             }42             43             result += String(remainder / denominator)44             45             //Set our repeater..46             repeatMap[remainder] = result.count - 147             48             //Perform one more step of long division49             remainder = (remainder % denominator) * 10 50         }51 52         if negative == true {53             return String("-") + result54         }55         return result56     }57 }

12ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3          4         if numerator  == 0 { 5             return "0" 6         } 7          8         var res = "" 9         10         if ((numerator < 0) && (denominator >= 0)) || ((numerator >= 0) && (denominator < 0)) {11             res += "-"12         }13         14         let absNum = abs(numerator)15         let absDen = abs(denominator)16         17         res += String(absNum/absDen)18         19         var remander = absNum % absDen20         21         if remander == 0 {22             return res23         }24         25         res += "."26         27         var remanders = [Int : Int]()28         29         var pos = res.count30         31         var add = 032         var hasRecycyle = false33         34         while remander != 0 && !hasRecycyle {35             if remanders.keys.contains(remander) {36                 add = remanders[remander]!37                 hasRecycyle = true38                 continue39             }40             41             remanders[remander] = pos42             pos += 143             res += String(10 * remander / absDen)44             remander = (10 * remander) % absDen45         }46         47         if hasRecycyle {48             res.insert("(",at: res.index(res.startIndex,offsetBy: add))49             res += ")"50         }51         52         53         return res54     }55 }

16ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3         var s1:Int = numerator >= 0 ? 1 : -1 4         var s2:Int = denominator >= 0 ? 1 : -1 5         var num:Int = abs(numerator ) 6         var den:Int = abs(denominator ) 7         var out:Int = num / den 8         var rem:Int = num % den 9         var m:[Int: Int] = [Int: Int]()10         var res:String = String(out)11         if s1 * s2 == -1 && (out > 0 || rem > 0)12         {13             res = "-" + res14         }15         if rem == 0 {return res}16         res += "."17         var s:String = ""18         var pos:Int = 019         while(rem != 0)20         {21             if m[rem] != nil22             {23                 var index = s.index(s.startIndex,offsetBy: m[rem]!)24                 s.insert("(",at:index )25                 s += ")"26                 return res + s27             }28             m[rem] = pos29             s += String((rem * 10) / den)30             rem = (rem * 10) % den31             pos += 132         }33         return res + s34     }35 }

20ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3          4         if numerator % denominator == 0 { 5             return String(numerator/denominator) 6         } 7          8         let n = abs(numerator); 9         let d = abs(denominator);10         11         var sign = ""12         13         if numerator > 0 && denominator < 0 || numerator < 0 && denominator > 0{14             sign = "-"15         }16         17         var i = n18         while i > d {19             i = i/d20         }21         22         var dic = Dictionary<Int,Int>()23         24         var res = n % d;25         var s = String()26         27         var count = 028         29         repeat {30             dic[res] = count31             res = res * 10;32             s.append(String(abs(res/d)))33             res = res % d34             count = count + 135         } while (res != 0 && dic[res] == nil)36         37         if res == 0 {38             return sign + String(n/d) + "." + s;39         }40         let IDx = s.index(s.startIndex,offsetBy: dic[res]!)41         return sign + String(n/d) + "." + s.substring(to: IDx) + "(" + s.substring(from: IDx) + ")"42     }43 }

20ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3         let r = numerator % denominator 4         let k = numerator / denominator 5         if r == 0 { 6             return "\(k)" 7         } 8          9         let tail = helper(abs(r),abs(denominator))10         var ret = "\(abs(k)).\(tail)"11         if numerator * denominator < 0 {12             ret = "-" + ret13         }14         return ret15     }16     17     18     func helper(_ n: Int,_ m: Int) -> String {19         var ret = ""20         var map = [Int: Int]()21         var x = n22         while x != 0 {23             if let i = map[x] {24                 ret = ret.prefix(i) + "(" + ret.suffix(ret.count - i) + ")"25                 return ret26             }27             let y = x * 1028             let k = y / m29             map[x] = ret.count30             ret += "\(k)"31             x = y % m32         }33         return ret34     }35 }

36ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3          if denominator == 0 { 4             return "" 5         } 6          7         if numerator == 0 { 8             return "0" 9         }10         11         //取绝对值12         var num1 = numerator > 0 ? numerator : -numerator13         let num2 = denominator > 0 ? denominator : -denominator14         //取方向15         var  result = (numerator > 0 && denominator < 0) || (numerator < 0 && denominator > 0) ? "-" : ""16         17         //整数部分18         result += String(num1/num2)19         num1 = num1 % num220         if num1 == 0 {21             return result22         }else {23             result += "."24         }25         26         //小数部分27         var dic = [Int:Int]()28         29         while num1 != 0 {30             if dic.keys.contains(num1) {31                 let index = result.index(result.startIndex,offsetBy: dic[num1]!)32                 result.insert("(",at: index)33                 result += ")"34                 break35             }36             dic[num1] = result.count37             num1 *= 1038             result += String(num1/num2)39             num1 %= num240         }41         return result42     }43 }

56ms

 1 class Solution { 2     func fractionToDecimal(_ numerator: Int,_ denominator: Int) -> String { 3         if numerator == 0 { return "0" } 4         let sign = (numerator > 0 ? 1 : -1) ^ (denominator > 0 ? 1 : -1) == 0 ? "" : "-" 5         var result = sign 6         var a = abs(numerator) 7         let b = abs(denominator) 8         result += "\(a/b)" 9         a = a % b10         if a != 0 {11             result += "."12         } else {13             return result14         }15         var decimal = ""16         var array = [a]17         while true {18             a = a * 1019             decimal += "\(a/b)"20             a = a % b21             if a == 0 {22                 result += decimal23                 return result24             }25             if let index = array.index(of: a) {26                 var temp = [Character](decimal)27                 temp.insert("(",at: index)28                 temp.append(")")29                 result += String(temp)30                 return result31             } else {32                 array.append(a)33             }34         }35     }36 }

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