Create the-number-of-passengers-in-each-bus-i.sql

Author: kamyu104

MySQL/the-number-of-passengers-in-each-bus-i.sql

@@ -0,0 +1,19 @@
+# Time:  O(p * b + blogb)
+# Space: O(p * b)
+
+WITH arrival_time_cte AS
+(
+    SELECT passenger_id, MIN(b.arrival_time) AS arrival_time
+    FROM Passengers p
+    INNER JOIN Buses b
+    ON p.arrival_time <= b.arrival_time
+    GROUP BY passenger_id
+    ORDER BY NULL
+)
+
+SELECT bus_id, COUNT(a.arrival_time) AS passengers_cnt
+FROM Buses b
+LEFT JOIN arrival_time_cte a
+ON b.arrival_time = a.arrival_time
+GROUP BY bus_id
+ORDER BY bus_id;