Simple scheduling algorithm in python (using Fenwick Trees)

schedule.py

class Fenwick:
    def __init__(self, n):
        self.n = n+1
        self.T = [0] * self.n

    def adjust(self, k, v):
        k+=1
        while k < self.n:
            self.T[k] += v
            k += k&-k
        
    def rsq(self, b):
        b+=1
        result = 0
        while b:
            result += self.T[b]
            b -= b&-b
        return result

def schedule(tasks):
    started = Fenwick(24)
    finished = Fenwick(24)

    def offer(begin, end):
        result = started.rsq(end-1)-finished.rsq(begin)
        started.adjust(begin, 1)
        finished.adjust(end, 1)
        return result+1
    
    return ((offer(begin, end), (begin, end)) for begin, end in tasks)

for room, meeting in schedule([(12,13), (13,15), (19, 21), (18, 20), (17,20), (13,14)]):
    print 'Meeting {} should occur in room {}'.format(meeting, room)