add Meeting Rooms II solution

Author: HoonDongKang

meeting-rooms-ii/HoonDongKang.ts

@@ -0,0 +1,44 @@
+/**
+ * [Problem]: [919] Meeting Rooms II
+ * (https://www.lintcode.com/problem/919/)
+ */
+
+export class Interval {
+    start: number;
+    end: number;
+    constructor(start: number, end: number) {
+        this.start = start;
+        this.end = end;
+    }
+}
+
+// 시간복잡도 O(n log n)
+// 공간복잡도 O(n)
+export class Solution {
+    /**
+     * @param intervals: an array of meeting time intervals
+     * @return: the minimum number of conference rooms required
+     */
+    minMeetingRooms(intervals: Interval[]): number {
+        if (intervals.length === 0) return 0;
+
+        const starts = intervals.map((i) => i.start).sort((a, b) => a - b);
+        const ends = intervals.map((i) => i.end).sort((a, b) => a - b);
+
+        let count = 0;
+        let maxCount = 0;
+        let endIdx = 0;
+
+        for (let i = 0; i < intervals.length; i++) {
+            if (starts[i] < ends[endIdx]) {
+                count++;
+            } else {
+                endIdx++;
+            }
+
+            maxCount = Math.max(maxCount, count);
+        }
+
+        return maxCount;
+    }
+}