hdu 1116 Play on Words

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

const int maxn=100010;
int sumru[maxn],sumchu[maxn],father[30],flag[30],ff[30];
char s[1000];

int findd(int x)
{
if(x!=father[x]) father[x]=findd(father[x]);
return father[x];
}

int main()
{
int T;
scanf("%d",&T);
while(T--)
{
int n,i;

scanf("%d",&n);
memset(sumru,0,sizeof(sumru));
memset(sumchu,0,sizeof(sumchu));
memset(flag,0,sizeof(flag));
memset(ff,0,sizeof(ff));
for(i=0;i<=25;i++) father[i]=i;

for(i=0;i<n;i++)
{
scanf("%s",s);
sumru[s[strlen(s)-1]-'a']++;
sumchu[s[0]-'a']++;
int ft=findd(s[0]-'a');
int fw=findd(s[strlen(s)-1]-'a');
if(ft!=fw) father[ft]=fw;
flag[s[strlen(s)-1]-'a']=1;
flag[s[0]-'a']=1;
}

int jieguo=1,tott=0;
int uu[maxn];

for(i=0;i<=25;i++) if(flag[i]==1) ff[findd(i)]=1;
for(i=0;i<=25;i++) if(ff[i]==1) tott++;
if(tott!=1)jieguo=0;
tott=0;
if(jieguo==1)
{
for(i=0;i<=25;i++)
{
if(sumru[i]==0&&sumchu[i]==0) continue;//这个点没有出现
if(sumru[i]==sumchu[i]) continue;
if(sumru[i]!=sumchu[i])
{
uu[tott]=i;
tott++;
}
}
if(tott!=2&&tott!=0) jieguo=0;
if(tott==2)
{
if((sumru[uu[0]]-sumchu[uu[0]]==1&&sumru[uu[1]]-sumchu[uu[1]]==-1)||(sumru[uu[0]]-sumchu[uu[0]]==-1&&sumru[uu[1]]-sumchu[uu[1]]==1)) jieguo=jieguo;
else jieguo=0;
}
}

if(jieguo==0) printf("The door cannot be opened.\n");
else printf("Ordering is possible.\n");
}
return 0;
}