Valid sudoku & fraction to decimal leetcode problem solved

Author: jyotisirswa

DataStrucutureQuestions/HashMap/166. Fraction to Recurring Decimal.playground/Contents.swift

@@ -0,0 +1,45 @@
+import UIKit
+
+//https://leetcode.com/problems/fraction-to-recurring-decimal/
+
+
+
+func fractionToDecimal(_ numerator: Int, _ denominator: Int) -> String {
+    var result = ""
+    var remainderMap : [Int : Int] = [:]
+    if numerator == 0 {
+        return "0"
+    }
+    
+    if numerator < 0 || denominator < 0 {
+        result.append("-")
+    }
+    
+    var quotient = abs(numerator/denominator)
+    result += "\(quotient)"
+    var remainder = (numerator % denominator) * 10
+    if remainder == 0 {
+        return result
+    } else {
+        result += "."
+    }
+    
+    while remainder != 0 {
+        if remainderMap[remainder] != nil {
+            let beginning = remainderMap[remainder]
+            let left = result[result.index(result.startIndex, offsetBy: 0)..<result.index(result.startIndex, offsetBy: beginning ?? 0)]
+            let right = result[result.index(result.startIndex, offsetBy: beginning ?? 0)..<result.index(result.startIndex, offsetBy: result.count)]
+            result = left + "(" + right + ")"
+            return result
+        } else {
+            remainderMap[remainder] = result.count
+            quotient = remainder/denominator
+            result += "\(quotient)"
+            remainder = (remainder % denominator) * 10
+        }
+    }
+    return result
+}
+
+print(fractionToDecimal(4, 333))
+print(fractionToDecimal(1, 2))

DataStrucutureQuestions/HashMap/166. Fraction to Recurring Decimal.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true' importAppTypes='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

DataStrucutureQuestions/Matrix/36. Valid Sudoku.playground/Contents.swift

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+import UIKit
+
+//https://leetcode.com/problems/valid-sudoku/description/
+
+func isValidSudoku(_ board: [[Character]]) -> Bool {
+   var col = [Int : Set<Character>]()
+   var row = [Int : Set<Character>]()
+   var square = [Int : Set<Character>]() //keys r/3 * 3 + c/3
+   
+    for r in 0..<9 {
+       for c in 0..<9 {
+           let value = board[r][c]
+           if value == "." {
+               continue
+           }
+           if row[r]?.contains(value) == true || col[c]?.contains(value) == true || square[(r/3)*3 + c/3]?.contains(value) == true {
+               return false
+           }
+           row[r, default: Set<Character>()].insert(value)
+           col[c, default: Set<Character>()].insert(value)
+           square[(r/3)*3 + c/3, default: Set<Character>()].insert(value)
+       }
+   }
+    return true
+}
+
+print(isValidSudoku([["5","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],[".","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4",".",".","8",".","3",".",".","1"],["7",".",".",".","2",".",".",".","6"],[".","6",".",".",".",".","2","8","."],[".",".",".","4","1","9",".",".","5"],[".",".",".",".","8",".",".","7","9"]]))

DataStrucutureQuestions/Matrix/36. Valid Sudoku.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true' importAppTypes='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>