1109. Corporate Flight Bookings

1. Question

There are n flights that are labeled from 1 to n.

You are given an array of flight bookings bookings, where bookings[i] = [first_i, last_i, seats_i] represents a booking for flights first_i through last_i (inclusive) with seats_i seats reserved for each flight in the range.

Return an array answer of length n, where answer[i] is the total number of seats reserved for flight i.

2. Examples

Example 1:

Input: bookings = [[1,2,10],[2,3,20],[2,5,25]], n = 5
Output: [10,55,45,25,25]
Explanation:
Flight labels:        1   2   3   4   5
Booking 1 reserved:  10  10
Booking 2 reserved:      20  20
Booking 3 reserved:      25  25  25  25
Total seats:         10  55  45  25  25
Hence, answer = [10,55,45,25,25]

Example 2:

Input: bookings = [[1,2,10],[2,2,15]], n = 2
Output: [10,25]
Explanation:
Flight labels:        1   2
Booking 1 reserved:  10  10
Booking 2 reserved:      15
Total seats:         10  25
Hence, answer = [10,25]

3. Constraints

• 1 <= n <= 2 * 10⁴
• 1 <= bookings.length <= 2 * 10⁴
• bookings[i].length == 3
• 1 <= first_i <= last_i <= n
• 1 <= seats_i <= 10⁴

4. References

来源：力扣（LeetCode） 链接：https://leetcode-cn.com/problems/corporate-flight-bookings 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

5. Solutions

区间加法——差分

前缀+差分

class Solution {
    public int[] corpFlightBookings(int[][] bookings, int n) {
        int[] arr = new int[n];
        for (int i = 0; i < bookings.length; i++) {
            arr[bookings[i][0] - 1] += bookings[i][2];
            if (bookings[i][1] < n) {
                arr[bookings[i][1]] -= bookings[i][2];
            }
        }
        for (int i = 1; i < arr.length; i++) {
            arr[i] += arr[i - 1];
        }
        return arr;
    }
}