0681-next-closest-time

0681-next-closest-time.playground/Contents.swift

@@ -0,0 +1,38 @@
+/// 681. Next Closest Time
+/// Given a time represented in the format "HH:MM", form the next closest time by reusing the
+/// current digits. There is no limit on how many times a digit can be reused.
+/// You may assume the given input string is always valid. For example, "01:34", "12:09" are all
+/// valid. "1:34", "12:9" are all invalid.
+
+import XCTest
+
+/// Approach: String
+func nextClosestTime(_ time: String) -> String {
+    guard time.count == 5 else { fatalError() }
+    let timeChars = Array(time)
+    let hh = Int(String(timeChars[0..<2]))!
+    let mm = Int(String(timeChars[3..<5]))!
+    var m = (mm + 1) % 60
+    var h = m == 0 ? (hh + 1) % 24 : hh
+    let timeSet = Set(timeChars)
+    while h != hh || m != mm {
+        let hStr = h > 9 ? String(h) : "0" + String(h)
+        let mStr = m > 9 ? String(m) : "0" + String(m)
+        let nextTime = hStr + ":" + mStr
+        if Set(Array(nextTime)).isSubset(of: timeSet) {
+            return nextTime
+        }
+        m = (m + 1) % 60
+        h = m == 0 ? (h + 1) % 24 : h
+    }
+    return time
+}
+
+class Tests: XCTestCase {
+    func testExample() {
+        let time = "19:34"
+        XCTAssertEqual(nextClosestTime(time), "19:39")
+    }
+}
+
+Tests.defaultTestSuite.run()

0681-next-closest-time.playground/contents.xcplayground

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

README.md

@@ -51,3 +51,4 @@ You can visit the pages below to search problems by company tags. Then come back
 31 | [Next Permutation](https://leetcode.com/problems/next-permutation/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0031-next-permutation.playground/Contents.swift) | Two Pointers
 32 | [Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0032-longest-valid-parentheses.playground/Contents.swift) | Stack
 33 | [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0033-search-in-rotated-sorted-array.playground/Contents.swift) | Binary Search
+681 | [Next Closest Time](https://leetcode.com/problems/next-closest-time/description/) | [Solution](https://github.com/zhubofei/LeetCode-Swift/blob/master/0681-next-closest-time.playground/Contents.swift) | Simulation