POJ 1703

 1 #include<iostream>
 2 #include<stdio.h>
 3 #define MAXN 100002
 4 using namespace std;
 5 
 6 int pre[MAXN];
 7 int root[MAXN];
 8 int enemy[MAXN];
 9 
10 void init(int n)
11 {
12     int i;
13     for(i = 1; i <= n; ++ i)
14     {
15         pre[i] = i;
16         root[i] = 0;
17         enemy[i] = -1;
18     }
19 }
20 
21 int find_pre(int x)
22 {
23     if(pre[x] != x)
24     {
25         pre[x] = find_pre(pre[x]);
26     }
27     return pre[x];
28 }
29 
30 int comb(int x,int y)
31 {
32     if(x == -1)
33         return y;
34     if(y == -1)
35         return x;
36     //if(root[x] > root[y])
37     //{
38         pre[y] = x;
39         return x;
40 //    }
41     //else
42     //{
43     //    pre[x] = y;
44     //    if(root[x] == root[y])
45     //        ++ root[y];
46     //    return y;
47     //}
48 }
49 
50 int main()
51 {
52     //freopen("acm.acm","r",stdin);
53     int test;
54     scanf("%d",&test);
55     int n;
56     int m;
57     int i;
58     char q;
59     int u;
60     int v;
61     int temp1;
62     int temp2;
63     while(test --)
64     {
65         scanf("%d%d",&n,&m);
66         init(n);
67         for(i = 0; i < m; ++ i)
68         {
69             cin>>q;
70             if(q == ‘D‘)
71             {
72                 scanf("%d%d",&u,&v);
73                 temp1 = find_pre(v);
74                 temp2 = find_pre(u);
75                 u = comb(temp1,enemy[temp2]);
76                 v = comb(enemy[temp1],temp2);
77                 enemy[u] = v;
78                 enemy[v] = u;
79             }
80             else
81             {
82                 scanf("%d%d",&u,&v);
83                 temp1 = find_pre(u);
84                 temp2 = find_pre(v);
85                 if(temp1 == temp2)
86                     cout<<"In the same gang."<<endl;
87                 else if(temp1 == enemy[temp2])
88                 {
89                     cout<<"In different gangs."<<endl;
90                 }
91                 else
92                 {
93                     cout<<"Not sure yet."<<endl;
94                 }
95             }
96         }
97     }
98 }