Uber Rides

Uber has several cabs. The i^th cab takes cabTripTime[i] minutes to complete any trip. Your task is to find the minimum time it will take Uber to get n trips completed with these cabs. You can assume there is no waiting time in-between the trips.

Note: Different cabs can take trips simultaneously (at any time, there can be more than one cab with an ongoing trip)

Example 1:

Input: n = 3, cabTripTime = [1, 2]
Output: 2
Explanation:
Trips can be managed like this:
- Trip 1: first cab from t = 0 to t = 1;
- Trip 2: second cab from t = 0 to t = 2;
- Trip 3: first cab from t = 1 to t = 2.

All the trips can be completed in 2 minutes. In 1 minute the cabs finish only 1 + 0 = 1 trip, so the answer is 2.

Example 2:

Input: n = 10, cabTripTime = [1, 3, 5, 7]
Output: 7
Explanation:
Trips can be managed like this:
- Trip 1: 1st cab from t = 0 to t = 1;
- Trip 2: 2nd cab from t = 0 to t = 3;
- Trip 3: 3rd cab from t = 0 to t = 5;
- Trip 4: 4th cab from t = 0 to t = 7;
- Trip 5: 1st cab from t = 1 to t = 2;
- Trip 6: 1st cab from t = 2 to t = 3;
- Trip 7: 1st cab from t = 3 to t = 4;
- Trip 8: 2nd cab from t = 3 to t = 6;
- Trip 9: 1st cab from t = 4 to t = 5;
- Trip 10: 1st cab from t = 5 to t = 6.

All the trips can be completed in 7 minutes. In 6 minutes the cabs finish at most 6 + 2 + 1 + 0 = 9 trips, so the answer is 7.