DFS/并查集 Codeforces Round #286 (Div. 2) B - Mr. Kitayuta's Colorful Graph

题目传送门

 /*
     题意：两点之间有不同颜色的线连通，问两点间单一颜色连通的路径有几条
     DFS：暴力每个颜色，以u走到v为结束标志，累加条数
     注意：无向图
 */
 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <cstring>
 #include <string>
 #include <vector>
 using namespace std;

 const int MAXN = 1e2 + ;
 const int INF = 0x3f3f3f3f;
 int n, m;
 bool vis[MAXN];
 vector<pair<int, int> > V[MAXN];

 bool DFS(int u, int v, int c)
 {
     vis[u] = true;
     if (u == v)    return true;
     for (int i=; i<V[u].size (); ++i)
     {
         pair<int, int>  p = V[u][i];
         if (p.second == c && !vis[p.first])
         {
             if (DFS (p.first, v, c))    return true;
         }
     }

     return false;
 }

 int main(void)        //Codeforces Round #286 (Div. 2) B - Mr. Kitayuta's Colorful Graph
 {
     //freopen ("B.in", "r", stdin);

     while (scanf ("%d%d", &n, &m) == )
     {
         for (int i=; i<=m; ++i)
         {
             int u, v, c;
             scanf ("%d%d%d", &u, &v, &c);
             V[u].push_back (make_pair (v, c));
             V[v].push_back (make_pair (u, c));
         }
         int q;    scanf ("%d", &q);
         while (q--)
         {
             int u, v;    scanf ("%d%d", &u, &v);
             int ans = ;
             for (int i=; i<=m; ++i)
             {
                 memset (vis, false, sizeof (vis));
                 if (DFS (u, v, i))    ans++;
             }
             printf ("%d\n", ans);
         }
     }

     return ;
 }

 /*
     并查集：开在结构体的并查集，进行如下的两个操作
     uf[c].Union (u, v);    uf[i].same (u, v)
 */
 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <cstring>
 #include <vector>
 using namespace std;

 const int MAXN = 1e2 + ;
 const int INF = 0x3f3f3f3f;
 struct UF
 {
     int rt[MAXN];
     void init(void)    {memset (rt, -, sizeof (rt));}

     int Find(int x)    {return (rt[x] == -) ? x : rt[x] = Find (rt[x]);}

     void Union(int x, int y)
     {
         int tx = Find (x);
         int ty = Find (y);
         if (tx > ty)    rt[ty] = tx;
         else if (tx < ty)    rt[tx] = ty;
     }

     bool same(int x, int y)
     {
         return (Find (x) == Find (y));
     }
 }uf[MAXN];
 int n, m;

 int main(void)        //Codeforces Round #286 (Div. 2) B - Mr. Kitayuta's Colorful Graph
 {
     //freopen ("B.in", "r", stdin);

     while (scanf ("%d%d", &n, &m) == )
     {
         for (int i=; i<=m; ++i)    uf[i].init ();
         for (int i=; i<=m; ++i)
         {
             int u, v, c;
             scanf ("%d%d%d", &u, &v, &c);
             uf[c].Union (u, v);
         }
         int q;    scanf ("%d", &q);
         while (q--)
         {
             int u, v;    scanf ("%d%d", &u, &v);
             int ans = ;
             for (int i=; i<=m; ++i)
             {
                 if (uf[i].same (u, v))    ans++;
             }
             printf ("%d\n", ans);
         }
     }

     return ;
 }

并查集