图论/暴力 Codeforces Beta Round #94 (Div. 2 Only) B. Students and Shoelaces

 1 /*
 2     图论/暴力：这是个连通的问题，每一次把所有度数为1的砍掉，把连接的点再砍掉，总之很神奇，不懂:)
 3 */
 4 #include <cstdio>
 5 #include <cstring>
 6 #include <algorithm>
 7 #include <cmath>
 8 using namespace std;
 9 
10 const int MAXN = 1e2 + 10;
11 const int INF = 0x3f3f3f3f;
12 int cnt[MAXN];
13 int a[MAXN];
14 bool g[MAXN][MAXN];
15 
16 int main(void)        //Codeforces Beta Round #94 (Div. 2 Only) B. Students and Shoelaces
17 {
18 //    freopen ("B.in", "r", stdin);
19     int n, m;
20     while (scanf ("%d%d", &n, &m) == 2)
21     {
22         memset (cnt, 0, sizeof (cnt));
23         memset (g, false, sizeof (g));
24         for (int i=1; i<=m; ++i)
25         {
26             int x, y;    scanf ("%d%d", &x, &y);
27             cnt[x]++;    cnt[y]++;
28             g[x][y] = g[y][x] = true;
29         }
30 
31         int t = 0;    int ans = -1;
32         do{
33             t = 0;
34             for (int i=1; i<=n; ++i)
35             {
36                 if (cnt[i] == 1)    {cnt[i]--;    a[++t] = i;}
37             }
38             for (int i=1; i<=t; ++i)
39             {
40                 for (int j=1; j<=n; ++j)
41                 {
42                     if (g[a[i]][j] == true)    cnt[j]--;
43                 }
44             }
45             ++ans;
46         }while (t > 0);
47 
48         printf ("%d\n", ans);
49     }
50 
51     return 0;
52 }
53 
54 
55 /*
56 3 3
57 1 2
58 2 3
59 3 1
60 6 3
61 1 2
62 2 3
63 3 4
64 6 5
65 1 4
66 2 4
67 3 4
68 5 4
69 6 4
70 */