a121: 質數又來囉

http://zerojudge.tw/ShowProblem?problemid=a121

• MAX=10000
• is_prime=[False,False]+[True]*(MAX-1)
• primes=[]
• now=2
• while True:
•   primes.append(now)
•   for i in range(now*2,MAX+1,now):
•     is_prime[i]=False
•   now+=1
•   try:
•     while is_prime[now]==False:
•       now+=1
•   except:
•     break
•  
• while True:
•   try:
•     a,b=input().split()
•     a,b=int(a),int(b)
•     count=0
•     for x in range(a,b+1):
•       if x<=MAX:
•         if x in primes:
•           count+=1
•       else:
•         for prime in primes:
•           if x%prime==0:
•             break
•         else:  # a loop’s else clause runs when no break occurs
•           count+=1
•     print(count)
•   except:
•     break