uva 10129 poj 1386 hdu 1116 zoj 2016 play on words

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cmath>
 4 #include<algorithm>
 5 #include<cstring>
 6 #include<cstdlib>
 7 #include<queue>
 8 #include<vector>
 9 #include<map>
10 #include<stack>
11 #include<string>
12 
13 using namespace std;
14 
15 int T,n;
16 int in[26],out[26];
17 int f[26];
18 char s[1007];
19 
20 int gf(int x){
21     if (x==f[x]) return f[x];
22     f[x]=gf(f[x]);
23     return f[x];
24 }
25 
26 bool solve(){
27             memset(in,0,sizeof(in));
28             memset(out,0,sizeof(out));
29             for (int i=0;i<26;i++){
30                     f[i]=i;
31             }
32             scanf("%d",&n);
33             for (int i=0;i<n;i++){
34                     scanf("%s",s);
35                     int f1=gf(s[0]-‘a‘);
36                     int f2=gf(s[strlen(s)-1]-‘a‘);
37                     if (f1!=f2){
38                             f[f1]=f2;
39                     }
40                     in[s[0]-‘a‘]++;
41                     out[s[strlen(s)-1]-‘a‘]++;
42             }
43             int pre=-1;
44             for (int i=0;i<26;i++){
45                     if (in[i]!=0 || out[i]!=0){
46                             if (pre==-1)
47                                 pre=gf(i);
48                             else{
49                                     if (pre!=gf(i)) return false;
50                                     pre=gf(i);
51                             }
52                     }
53             }
54             for (int i=0;i<26;i++){
55                     in[i]=in[i]-out[i];
56             }
57             sort(in,in+26);
58             for (int i=1;i<25;i++) if (in[i]!=0) return false;
59             if (abs(in[0])>1 || abs(in[25])>1 || in[0]+in[25]!=0) return false;
60             if (in[0]+in[25]!=0) return false;
61             return true;
62 }
63 
64 int main(){
65     scanf("%d",&T);
66     for (int cas=1;cas<=T;cas++){
67             if (solve())
68                 printf("Ordering is possible.\n");
69             else
70                 printf("The door cannot be opened.\n");
71     }
72     return 0;
73 }
74 /*
75 3
76 2
77 acm
78 ibm
79 3
80 acm
81 malform
82 mouse
83 2
84 ok
85 ok
86 */