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There are n flights, and they are labeled from 1 to n.

We have a list of flight bookings. The i-th booking bookings[i] = [i, j, k] means that we booked k seats from flights labeled i to j inclusive.

Return an array answer of length n, representing the number of seats booked on each flight in order of their label.

Example 1:

Input: bookings = [[1,2,10],[2,3,20],[2,5,25]], n = 5
Output: [10,55,45,25,25]

Constraints:

1 <= bookings.length <= 20000
1 <= bookings[i][0] <= bookings[i][1] <= n <= 20000
1 <= bookings[i][2] <= 10000

running sum,也叫扫描线,重点在于一个interval有一个值的情况下,我们只看变化的index和变化值,最后叠加就是最终答案。

Intuition
Since ranges are continuous, what if we add reservations to the first flight in the range, and remove them after the last flight in range? We can then use the running sum to update reservations for all flights.

This picture shows the logic for this test case: [[1,2,10],[2,3,20],[3,5,25]].

public int[] corpFlightBookings(int[][] bookings, int n) {
  int[] res = new int[n];
  for (int[] v : bookings) {
    res[v[0] - 1] += v[2];
    if (v[1] < n) res[v[1]] -= v[2];
  }
  for (int i = 1; i < n; ++i) res[i] += res[i - 1];
  return res;
}

本文标签: CorporateBookingsFlight