joj 1078 hdu 1116

欧拉回路 在加上 并查集判断连通性，把每一个单词当做一个边,话说我一开始当做h路做的。。。。。

#include<iostream>
#include<stdio.h>
#include<string>
using namespace std;
int father[26],rank[26],r[26],c[26],mark[26];
int find(int x)
{   //cout<<11111<<endl;
    if(father[x]==x)
        return x;
    else
        return father[x]=find(father[x]);
}
void uion(int m,int n)
{
     int x=find(m);
     int y=find(n);
     if(rank[x]==rank[y])
     {
         rank[x]++;
         father[y]=x;
     }
     else if(rank[x]>rank[y])
     {
         father[y]=x;
     }
     else
     {
         father[x]=y;
     }
}
int main()
{
    int total_case,iii;
    scanf("%d",&total_case);
    for(iii=0;iii<total_case;iii++)
    {
        int i,n,mm=0;
        memset(mark,0,sizeof(mark));
        memset(rank,0,sizeof(rank));
        memset(r,0,sizeof(r));
        memset(c,0,sizeof(c));
        for(i=0;i<26;i++)
            father[i]=i;
        scanf("%d",&n);
        //cout<<mark[i]<<endl;
        for(i=0;i<n;i++)
        {
            string s;
            cin>>s;
            int m=s[0]-'a',n=s[s.length()-1]-'a';
            mark[n]=1;
            mark[m]=1;
            uion(m,n);
            r[n]++;
            c[m]++;
              
                   
        }
        //cout<<mark[1]<<endl;
        int k=-1;
        for(i=0;i<26;i++)
        {
            if(mark[i]==1)
            {
                 if(k==-1)
                    k=find(father[i]);
                 else
                 {
                    if(k==find(father[i]))
                        continue;
                    else
                        mm=1;
                        break;
                 }    
            }
        }
        //cout<<mark[1]<<endl;
        //cout<<mark[1]<<endl;
        if(mm==0)
        {
            int ru=0,chu=0;
            for(i=0;i<26;i++)
            {
                if(r[i]==c[i])
                {
                }
                else if(ru==0&&r[i]-c[i]==1)
                     ru++;
                else if(chu==0&&c[i]-r[i]==1)
                     chu++;
                else
                {
                     mm=1;
                     break;
                }
            }
            if((ru==1&&chu==1)||(ru==0&&chu==0))
            {}
            else
                mm=1;
        }
        if(mm==0)
            printf("Ordering is possible.\n");
        else
            printf("The door cannot be opened.\n");
    }
}