UVa 1590 - IP Networks

#include<iostream>
#include<cstring>
#include<cstdio>
#define MAXN 1010
using namespace std;

int main() {
//    freopen("in.txt", "r", stdin);
int m, p[5], n = 0, d = 1 << 8;
char ip[MAXN][8 * 4 + 10], final_ip[32];
while(cin >> m) {
memset(p, 0, sizeof(0));
memset(ip, 0, sizeof(0));
memset(final_ip, 0, sizeof(0));
int max_len = 32;
for(int i = 1; i <= m; i++) {
scanf("%d.%d.%d.%d", &p[1], &p[2], &p[3], &p[4]);
ip[i][32] = '\0';
for(int j = 31; j >= 0; j--) {
ip[i][j] = p[j / 8 + 1] % 2;
p[j / 8 + 1] /= 2;
}
}
for(int i = 1; i < m; i++)
for(int j = i + 1; j <= m; j++)
for(int k = 0; k < 32; k++)
if(ip[i][k] != ip[j][k]) {
if(k < max_len)
max_len = k;
break;
}
for(int i = max_len; i < 32; i++)
ip[1][i] = 0;
for(int i = 0; i < 32; i++)
i < max_len ? final_ip[i] = 1 : final_ip[i] = 0;
for(int i = 0; i < 32; i++) {
d /= 2;
n += ip[1][i] * d;
if(d == 1) {
cout << n;
n = 0;
d <<= 8;
if(i != 31)
cout << ".";
}
}
cout << endl;
for(int i = 0; i < 32; i++) {
d /= 2;
n += final_ip[i] * d;
if(d == 1) {
cout << n;
n = 0;
d <<= 8;
if(i != 31)
cout << ".";
}
}
cout << endl;
}
return 0;
}