meeting rooms ii solution

Author: yhkee0404

meeting-rooms-ii/yhkee0404.kt

@@ -0,0 +1,35 @@
+/**
+ * Definition of Interval:
+ * class Interval {
+ *     var start: Int = 0
+ *     var end: Int = 0
+ *     constructor(start: Int, end: Int) {
+ *         this.start = start
+ *         this.end = end
+ *     }
+ * }
+ */
+
+class Solution {
+    /**
+     * @param intervals: an array of meeting time intervals
+     * @return: the minimum number of conference rooms required
+     */
+    fun minMeetingRooms(intervals: List<Interval?>): Int {
+        // Write your code here
+        val points = mutableListOf<List<Int>>()
+        intervals.filterNotNull() // T(n) = O(nlogn)
+                .forEach {
+                    points.add(listOf(it.start, 1,))
+                    points.add(listOf(it.end, -1,))
+                }
+        var ans = 0
+        var cnt = 0
+        points.sortedBy {it[0]} // T(n) = S(n) = O(n)
+                .forEach {
+                    cnt += it[1]
+                    ans = maxOf(ans, cnt,)
+                }
+        return ans
+    }
+}