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

 

题目传送门

 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 */