UVa 1590 - IP Networks

当初被这道题吓到了，其实是个水题。。。懒的写函数了，直接各种循环。

#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;
}