寻宝

代码

import sys
import math

while True:
    try:
        num = input()
        num = num.split(" ")
#         print(num)
        res ,target= 0,int(num[0])
        right ,left = int(num[1]),int(num[2])

        t = right - left
#         print([t,target,right,left])
        if t == 0:
            if target <= right:

                print(1)
            else:
                print(-1)
        elif t > 0:
            if target < 0:
                print(-1)
            else:
                res = 1 + int(math.ceil(abs(target - right)/ t))
                print(res)
#                 return
        else:
            if target > 0 and target > right:
                print(-1)
            else:
                print(math.ceil(abs(target)/abs(t)))
#             return ceil(abs(target)/abs(t))
        exit(0)
    except:
        break