source: https://leetcode.com/problems/corporate-flight-bookings/description/
There are n flights that are labeled from 1 to n.
You are given an array of flight bookings bookings, where bookings[i] = [firsti, lasti, seatsi] represents a booking for flights firsti through lasti (inclusive) with seatsi 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.
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]
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class Solution { public int[] corpFlightBookings(int[][] bookings, int n) { int[] seats = new int[n+1]; for(int [] booking: bookings){ int first = booking[0]; int last = booking[1]; int count = booking[2]; seats[first-1] = seats[first-1] + count; //to negate the effect when we calculate prefix sum seats[last] = seats[last]-count; } //calculate prefix sum for(int i=1;i<n;i++){ seats[i] = seats[i]+seats[i-1]; } return Arrays.copyOf(seats, n); } } |