[Swift]LeetCode1109. 航班预订统计 | Corporate Flight Bookings

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➤微信公众号：山青咏芝（shanqingyongzhi）
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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

---

这里有 n 个航班，它们分别从 1 到 n 进行编号。

我们这儿有一份航班预订表，表中第 i 条预订记录 bookings[i] = [i, j, k] 意味着我们在从 i 到 j 的每个航班上预订了 k 个座位。

请你返回一个长度为 n 的数组 answer，按航班编号顺序返回每个航班上预订的座位数。 

示例：

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

提示：

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

---

1224ms

class Solution {
    func corpFlightBookings(_ bookings: [[Int]], _ n: Int) -> [Int] {
        var solution = Array(repeating: 0, count: n)
        
        for booking in bookings {
            solution[booking[0]-1] += booking[2]
            if booking[1] < n { solution[booking[1]] -= booking[2] }
        }
        
        for i in 1..<n {
            solution[i] += solution[i-1]
        }
        
        return solution
    }
}

---

1240ms

class Solution {
    func corpFlightBookings(_ bookings: [[Int]], _ n: Int) -> [Int] {
        var diff = [Int](repeating: 0, count: n+1)
        for book in bookings {
            let start = book[0]
            let end = book[1]
            let count = book[2]
            diff[start-1] += count
            diff[end] -= count
        }
        
        var result = [Int](repeating: 0, count: n)
        for i in 0..<n {
            result[i] = (i - 1 >= 0 ? result[i-1] : 0) + diff[i]
        }
        return result
    }
}

---

1312ms

class Solution {
  func corpFlightBookings(_ bookings: [[Int]], _ n: Int) -> [Int] {
    var line = [Int](repeating: 0, count: n + 2)
    for b in bookings {
      line[b[0]] += b[2]
      line[b[1] + 1] -= b[2]
    }
    var res = [Int]()
    var r = 0
    for i in 1...n {
      r += line[i]
      res.append(r)
    }
    return res
  }
}

---

Runtime: 1336 ms

Memory Usage: 24.2 MB

class Solution {
    func corpFlightBookings(_ bookings: [[Int]], _ n: Int) -> [Int] {
        var res:[Int] = [Int](repeating:0,count:n) 
        for b in bookings
        {
            res[b[0] - 1] += b[2]
            if b[1] < n
            {
                res[b[1]] -= b[2]
            }
        }
        
        for i in 1..<n
        {
           res[i] += res[i - 1] 
        }
        return res        
    }
}