UVA 539 The Settlers of Catan(图的搜索)

来源：互联网发布：linux 搭建vps 编辑：程序博客网时间：2024/06/05 11:36

题意：有n个点m条边，求该图的最长一条链。

思路：很简单的图的搜索，以每个点为起点都搜一遍过，找出最长的。

//0 KB    18 ms#include#include#define M 30struct Edge{    int u,v,nxt;}edge[M*2];int head[M],vis[M*2];int n,m,ep,ans;void addedge(int cu,int cv){    edge[ep].v = cv;    edge[ep].nxt = head[cu];    head[cu] = ep++;    edge[ep].v = cu;    edge[ep].nxt = head[cv];    head[cv] = ep++;}void DFS(int u,int dep){    for (int i = head[u];i != -1;i = edge[i].nxt)    {        if (!vis[i])        {            ans = ans > (dep+1)? ans:(dep+1);            vis[i] = vis[i^1] = 1;    //是无向图，反向边也得标志            DFS(edge[i].v,dep+1);            vis[i] = vis[i^1] = 0;        }    }}int main (){    int i,j,u,v;    while (~scanf ("%d %d",&n,&m))    {        if (n == 0&&m == 0)            break;        memset (head,-1,sizeof(head));        ep = 0;        for (i = 0;i < m;i ++)        {            scanf("%d %d",&u,&v);            addedge(u,v);            //addedge(v,u);        }        ans = 0;        for(i = 0;i < n;i ++)        {            memset (vis,0,sizeof(vis));            DFS(i,0);        }        printf ("%d\n",ans);    }    return 0;}