POJ 2799 IP Networks
IP Networks
Time Limit: 1000MS
Memory Limit: 65536K
Total Submissions: 2159
Accepted: 815
Description
Alex is administrator of IP networks. His clients have a bunch of individual IP addresses and he decidedto group all those IP addresses into the smallest possible IP network.
Each IP address is a 4-byte number that is written byte-by-byte in a decimal dot-separated notation "byte0.byte1.byte2.byte3" (quotes are added for clarity). Each byte is written as a decimal number from0 to 255 (inclusive) without extra leading zeroes.
IP network is described by two 4-byte numbers - network address and network mask. Both networkaddress and network mask are written in the same notation as IP addresses.
In order to understand the meaning of network address and network mask you have to consider their binary representation. Binary representation of IP address, network address, and network mask consists of 32 bits: 8 bits for byte0 (most significant to least significant), followed by 8 bits for byte1, followed by 8 bits for byte2, and followed by 8 bits for byte3.
IP network contains a range of 2n IP addresses where 0 <= n <= 32. Network mask always has 32-n first bits set to one, and n last bits set to zero in its binary representation. Network address has arbitrary 32 - n first bits, and n last bits set to zero in its binary representation. IP network contains all IP addresses whose 32-n first bits are equal to 32-n first bits of network address with arbitrary n lastbits. We say that one IP network is smaller than the other IP network if it contains fewer IP addresses.
For example, IP network with network address 194.85.160.176 and network mask 255.255.255.248 contains 8 IP addresses from 194.85.160.176 to 194.85.160.183 (inclusive).
Input
The first line of the input contains a single integer number m (1 <= m <= 1000). The following m lines contain IP addresses, one address on a line. Each IP address may appear more than once in a case.
Output
Write to the output two lines that describe the smallest possible IP network that contains all IP addresses from this case. Write network address on the first line and network mask on the secondline.
Sample Input
3
194.85.160.177
194.85.160.183
194.85.160.178
Sample Output
194.85.160.176
255.255.255.248
#include
#include
#include
#include
#include
#include
#define ll __int64
using namespace std;
int n;
int a,b,c,d;
//告訴N個IP地址求其網絡地址及子網掩碼
//在同一個網段中,IP地址和子網掩碼按位與後等於該網段的網絡地址。
int main()
{
while(~scanf("%d",&n))
{
unsigned int maxs = 0;
unsigned int mins = 0-1;
unsigned int e;
for(int i=0;i>24,(ans<<8)>>24,(ans<<16)>>24,(ans<<24)>>24);
printf("%u.%u.%u.%u\n",mask>>24,(mask<<8)>>24,(mask<<16)>>24,(mask<<24)>>24);
}
return 0;
}