Student attendance record I.

Author: recherst

Easy/551.Student Attendance Record I.playground/Contents.swift

@@ -0,0 +1,64 @@
+/**
+ You are given a string s representing an attendance record for a student where each character signifies whether the student was absent, late, or present on that day. The record only contains the following three characters:
+
+ - 'A': Absent.
+ - 'L': Late.
+ - 'P': Present.
+ 
+ The student is eligible for an attendance award if they meet both of the following criteria:
+
+ - The student was absent ('A') for strictly fewer than 2 days total.
+ - The student was never late ('L') for 3 or more consecutive days.
+ 
+ Return true if the student is eligible for an attendance award, or false otherwise.
+
+  
+
+ Example 1:
+ Input: s = "PPALLP"
+ Output: true
+ Explanation: The student has fewer than 2 absences and was never late 3 or more consecutive days.
+ 
+ Example 2:
+ Input: s = "PPALLL"
+ Output: false
+ Explanation: The student was late 3 consecutive days in the last 3 days, so is not eligible for the award.
+  
+
+ Constraints:
+ - 1 <= s.length <= 1000
+ - s[i] is either 'A', 'L', or 'P'.
+ */
+class Solution {
+    func checkRecord(_ s: String) -> Bool {
+        if s.count == 1 { return true }
+        var absentCount = 0
+        var lateCount = 0
+        for (i, c) in s.enumerated() {
+            if absentCount == 2 || lateCount == 3 {
+                return false
+            }
+            if c == "A" {
+                absentCount += 1
+            } else if c == "L" {
+                if i == 0 {
+                    lateCount += 1
+                } else {
+                    if s[s.index(s.startIndex, offsetBy: i - 1)] == "L" {
+                        lateCount += 1
+                    } else {
+                        lateCount = 1
+                    }
+                }
+            }
+        }
+        if absentCount == 2 || lateCount == 3 {
+            return false
+        }
+        return true
+    }
+}
+
+let s = Solution()
+let r = s.checkRecord("LALL")
+print(r)

Easy/551.Student Attendance Record I.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>

Easy/551.Student Attendance Record I.playground/playground.xcworkspace/contents.xcworkspacedata

@@ -108,6 +108,7 @@
 104. [Detect Capital](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/520.Detect%20Captial.playground/Contents.swift)
 105. [Longest Uncommon Subsequence I](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/521.Longest%20Uncommon%20Subsequence%20I.playground/Contents.swift)
 106. [Reverse String II](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/541.Reverse%20String%20II.playground/Contents.swift)
+107. [Student Attendance Record I](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/551.Student%20Attendance%20Record%20I.playground/Contents.swift)
 
 #### Medium