1. class Diff:
    2.     def __init__(self,nums):
    3.         n = len(nums)
    4.         self.diff=[0]*(n)
    5.         for i in range(1,n):
    6.              self.diff[i]=nums[i]-nums[i-1]
    8.     def increment(self,i,j,val,n):
    9.         self.diff[i]+=val
    10.         if j+1<n:
    11.             self. diff[j+1]-=val
    13.     def result(self,n):
    14.         res =[0]*n
    15.         res[0]= self.diff[0]
    16.         for i in range(1,n):
    17.             res[i]=res[i-1]+ self.diff[i]
    18.         return res
    20. class Solution:
    21.     def corpFlightBookings(self, bookings: List[List[int]], n: int) -> List[int]:
    22.         diff = Diff([0]*n)
    23.         for booking in bookings:
    24.             first =booking[0]-1
    25.             last = booking[1]-1
    26.             val =booking[2]
    27.             diff.increment(first,last,val,n)
    28.         return diff.result(n)

    求最后加法的结果