[Array] Add comment for Task Scheduler

Author: soapyigu

Array/TaskScheduler.swift

@@ -1,6 +1,6 @@
 /**
  * Question Link: https://leetcode.com/problems/task-scheduler/
- * Primary idea: Most frequent character should be put at head of each chunk and join the chunks with less frequent one.
+ * Primary idea: Most frequent character should be put at head of each cycle and join the chunks with less frequent one.
  *
  * Time Complexity: O(nlogn), Space Complexity: O(n)
  *
@@ -16,6 +16,7 @@
         let sortedTasks = taskFreqs.keys.sorted { return taskFreqs[$0]! > taskFreqs[$1]! }
         var mostFreqCount = 0
 
+        // get interval number for last cycle
         for sortedTask in sortedTasks {
             if taskFreqs[sortedTask] != taskFreqs[sortedTasks[0]] {
                 break
@@ -24,6 +25,8 @@
             mostFreqCount += 1
         }
 
+        // when number of different tasks is greater than n + 1, and the most freqent task won't cause idle run,
+        // then we should return tasks.count
         return max(tasks.count, (taskFreqs[sortedTasks[0]]! - 1) * (n + 1) + mostFreqCount)
     }
-}
+}