feat: Solution for September Challenge 01 - Largest Time for Given Di…

…gits

Swift/September Challenge/01_LargestTimeForGivenDigits.playground/Contents.swift

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+/*:
+# 01. Largest Time for Given Digits
+https://leetcode.com/explore/challenge/card/september-leetcoding-challenge/554/week-1-september-1st-september-7th/3445/
+
+ ---
+
+### Problem Statement:
+
+ Given an array of 4 digits, return the largest 24 hour time that can be made.
+
+ The smallest 24 hour time is 00:00, and the largest is 23:59.  Starting from 00:00, a time is larger if more time has elapsed since midnight.
+
+ Return the answer as a string of length 5.  If no valid time can be made, return an empty string.
+
+
+### Example:
+
+ ```
+ Input: [1,2,3,4]
+ Output: "23:41"
+
+ Input: [5,5,5,5]
+ Output: ""
+
+ ```
+
+ ### Constraints:
+ + A.length == 4
+ + 0 <= A[i] <= 9
+
+
+ */
+
+
+import UIKit
+
+// 172 / 172 test cases passed.
+// Status: Accepted
+// Runtime: 12 ms
+// Memory Usage: 21.1 MB
+
+class Solution {
+    func largestTimeFromDigits(_ A: [Int]) -> String {
+        let sum = A.reduce(0, +)
+        if sum == 0 { return "00:00" }
+
+        var maxHour = 0
+        var maxMin = 0
+
+        for i in 0..<4 {
+            if A[i] > 2 { continue }
+
+            for j in 0..<4 {
+                if i == j { continue }
+
+                for k in 0..<4 {
+                    if k == i || k == j || A[k] > 6 { continue }
+
+                    for l in 0..<4 {
+                        if l == i || l == j || l == k { continue }
+
+                        let hours = A[i] * 10 + A[j]
+                        let minutes = A[k] * 10 + A[l]
+                        if hours < 24 && minutes < 60 {
+
+                            if hours == maxHour {
+                                maxMin = max(maxMin, minutes)
+                            } else if hours > maxHour {
+                                maxHour = hours
+                                maxMin = minutes
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        if maxHour == 0, maxMin == 0 { return "" }
+
+        let h = String(format: "%02d", maxHour)
+        let m = String(format: "%02d", maxMin)
+
+        return "\(h):\(m)"
+    }
+}
+
+class Solution1 {
+    func largestTimeFromDigits(_ A: [Int]) -> String {
+        var maxTime = Int.min
+        for i in 0..<A.count {
+            for j in 0..<A.count {
+                for k in 0..<A.count {
+                    let l = 6 - i - j - k
+                    if i != j, j != k, i != k, l >= 0 {
+                        let hour = A[i] * 10 + A[j]
+                        let minute = A[k] * 10 + A[l]
+                        if hour > 23 || minute > 59 {
+                            continue
+                        }
+                        maxTime = max(maxTime, hour * 60 + minute)
+                    }
+                }
+            }
+        }
+
+        if maxTime > Int.min {
+            let hour = maxTime / 60
+            let minute = maxTime % 60
+            return "\(hour/10)\(hour%10):\(minute/10)\(minute%10)"
+        }
+        return ""
+    }
+}
+
+let sol = Solution()
+sol.largestTimeFromDigits([1,2,3,4]) // "23:41"
+sol.largestTimeFromDigits([5,5,5,5]) // ""
+sol.largestTimeFromDigits([1,0,3,4]) // "14:30"
+

Swift/September Challenge/01_LargestTimeForGivenDigits.playground/contents.xcplayground

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