#1109

Corporate Flight Bookings

Medium
ArrayPrefix SumDifference ArrayPrefix Sum
LeetCode ↗

Approaches

Brute ForceOptimal
Complexity Comparison
Brute ForceOptimal Solution
Time
O(n²)
O(n)
Space
O(1)
O(n)
💡

Intuition

Time O(n)Space O(n)

The optimal approach uses a difference array technique to efficiently manage seat counts. This allows us to apply the bookings in constant time and then compute the final seat counts in a single pass.

⚙️

Algorithm

3 steps
  1. 1Step 1: Initialize an array 'answer' of size n with all elements set to 0.
  2. 2Step 2: For each booking, increment answer[first_i - 1] by seats_i and decrement answer[last_i] by seats_i (if last_i < n).
  3. 3Step 3: Iterate through the answer array and compute the prefix sum to get the total seats for each flight.
solution.py11 lines
1# Full working Python code
2
3def corpFlightBookings(bookings, n):
4    answer = [0] * (n + 1)
5    for first_i, last_i, seats_i in bookings:
6        answer[first_i - 1] += seats_i
7        if last_i < n:
8            answer[last_i] -= seats_i
9    for i in range(1, n):
10        answer[i] += answer[i - 1]
11    return answer[:-1]

Complexity note: The time complexity is O(n) because we process each booking in constant time and then compute the prefix sum in a single pass. The space complexity is O(n) due to the additional array used for the difference array technique.

  • 1Using a difference array allows for efficient range updates.
  • 2Prefix sums can be used to derive final results from incremental changes.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.