checkio的日子(2)

def checkio(data):
   data[0] += data[1]
   data[2] -= data[3]
   if int(data[0]) <= int(data[2]):
       checkio(data)
       if int(data[0]) > int(data[2]):
           if data[0] >= data[2] + data[3]:
               return data[2] + data[3]            
           else:
               return data[0]
   else:
       if data[0] >= data[2] + data[3]:
           return data[2] + data[3]
       else:
           return data[0]  
#Some hints
#Be careful with endless loop
#These "asserts" using only for self-checking and not necessary for auto-testing
if __name__ == '__main__':
   assert checkio([150, 50, 1000, 100]) == 450, "1st example"
   assert checkio([150, 50, 900, 100]) == 400, "2nd example"