Create 3439.swift

Author: Chiki1601

3001-3500/3439.swift

@@ -0,0 +1,28 @@
+class Solution {
+    func maxFreeTime(_ eventTime: Int, _ k: Int, _ startTime: [Int], _ endTime: [Int]) -> Int {
+        let n = startTime.count
+        var busy = 0
+        var ans = 0
+        
+        for i in 0..<k {
+            busy += endTime[i] - startTime[i]
+        }
+        
+        if n == k {
+            return eventTime - busy
+        }
+        
+        ans = startTime[k] - busy
+        
+        var i = 0
+        for r in k..<n {
+            busy += (endTime[r] - startTime[r]) - (endTime[i] - startTime[i])
+            let end = (r == n - 1) ? eventTime : startTime[r + 1]
+            let start = endTime[i]
+            ans = max(ans, end - start - busy)
+            i += 1
+        }
+        
+        return ans        
+    }
+}