poj2258 简单dfs The Settlers of Catan

http://poj.org/problem?id=2258

dfs 边是双向的 节点可以走多次 开个二维数组标记边 因为可以从任一节点出发所以n次dfs

View Code

 1 #include <stdio.h>

 2 #include<string.h>

 3 int x[26][26],v,w,n;

 4 void dfs(int i,int v)

 5 {

 6     int j;

 7     for(j = 0 ; j <= n-1 ; j++)

 8     {

 9         if(x[i][j] == 1)

10         {

11             x[i][j] = 0;

12             x[j][i] = 0;

13             dfs(j,v+1);

14             x[i][j] = 1;

15             x[j][i] = 1;

16         }

17     }

18     if(w<v)

19     w = v;

20 }

21 int main()

22 {

23     int m, i,j,a,b;

24     while(scanf("%d%d", &n, &m)!=EOF)

25     {

26         if(n == 0 && m == 0)

27         break;

28         memset(x,0,sizeof(x));

29         w = 0;

30         for(i = 1 ; i <= m ; i++)

31         {

32             scanf("%d%d", &a, &b);

33             x[a][b] = 1;

34             x[b][a] = 1;

35         }

36         for(i = 0 ; i <= n-1 ; i++)

37         {

38             dfs(i,0);

39         }

40         printf("%d\n", w);

41     }

42     return 0;

43 }