UVa-140 Bandwidth

#include <bits/stdc++.h>
#define _for(i,a,b) for(int i = (a);i < (b);i ++)
using namespace std;

const char a[27] = {'A','B','C','D','E','F','G','H','I','J',
                    'K','L','M','N','O','P','Q','R','S','T',
                    'U','V','W','X','Y','Z'
                   };
char s[393] {0};
int m[27][27] {0};
char rnts[39] {0};
int rnt = INT_MAX;
char ns[39] {0};
int n;

void addedge(int a,int b)
{
    m[a][b] = m[b][a] = 1;
}
void read()
{
    _for(i,0,strlen(s))
        if(s[i]==':')
            for(int j = i+1;s[j]!=''&&s[j]!=';';j ++)
                addedge(s[i-1]-'A',s[j]-'A');
}

void dfs()
{
    if(strlen(s)==1)
    {
        rnt = 0;
        rnts[0] = s[0];
        n = 1;
        return ;
    }
    int hash[27] {0};
    _for(i,0,27)
        _for(j,0,27)
            if(m[i][j])
                hash[j] ++;
    int ns_end = 0;
    _for(i,0,27)
        if(hash[i])
            ns[ns_end++] = 'A'+i;
    n = ns_end;
    do
    {
        int maxt = INT_MIN;
        _for(i,0,27)
        {
            int maxtn = INT_MIN;
            _for(j,0,27)
            {
                if(m[i][j])
                {
                    int ai,bi;
                    _for(k,0,27)
                    {
                        if(ns[k]=='A'+i)
                            ai = k;
                        if(ns[k]=='A'+j)
                            bi = k;
                    }
                    int trnt = abs(ai-bi);
                    maxtn = max(trnt,maxtn);
                }
            }
            maxt = max(maxt,maxtn);
            if(maxt>rnt)
                break;
        }
        if(maxt<rnt)
            strcpy(rnts,ns);
        rnt = min(rnt,maxt);
    }while(next_permutation(ns,ns+strlen(ns)));
}

void output()
{
    _for(i,0,n)
        printf("%c ",rnts[i]);
    printf("-> %d
",rnt);
}

int main()
{
    while(scanf("%s",s)==1 && s[0]!='#')
    {
        read();
        dfs();
        output();
        memset(s,0,sizeof(s));
        memset(m,0,sizeof(m));
        memset(ns,0,sizeof(ns));
        memset(rnts,0,sizeof(rnts));
        rnt = INT_MAX;
        n = 0;
    }
    return 0;
}

后悔上了邻接矩阵的贼船