10: determine the number of prime numbers.

10: determine the number of prime numbers.
10: determine the number of prime numbers

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Total time limit:

1000 ms

 

Memory limit:

65536kB

Description

Enter two integers X and Y to output the number of prime numbers (including X and Y) between them ).

Input

Two integers X and Y (1 <= X, Y <= 105 ).

Output

Returns an integer that represents the number of prime numbers (including X and Y) between X and Y ).

Sample Input

1 100

Sample output

25

 1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<cmath> 5 using namespace std; 6 char a[10001]; 7 int b[10001]; 8 int maxn=-1; 9 char ans=0;10 int beginn;11 int endn;12 int now;13 int tot;14 int flag=0;15 int main()16 {17     int x,y;18     cin>>x>>y;19     for(int i=min(x,y);i<=max(x,y);i++)20     {21         flag=0;22         for(int j=2;j<=sqrt(i);j++)23         {24             if(i%j==0)25             {26                 flag=1;27                 break;28             }29             30         }31         if(flag==0)32         tot++;33     }34     if(min(x,y)==1)35     cout<<tot-1;36     else cout<<tot;37     return 0;38 }