codeforces 505B——DFS——Mr. Kitayuta's Colorful Graph

Mr. Kitayuta has just bought an undirected graph consisting of n vertices and m edges. The vertices of the graph are numbered from 1 ton. Each edge, namely edge i, has a color ci, connecting vertex ai and bi.
Mr. Kitayuta wants you to process the following q queries.
In the i-th query, he gives you two integers — ui and vi.
Find the number of the colors that satisfy the following condition: the edges of that color connect vertex ui and vertex vi directly or indirectly.
Input
The first line of the input contains space-separated two integers — n and m (2 ≤ n ≤ 100, 1 ≤ m ≤ 100), denoting the number of the vertices and the number of the edges, respectively.
The next m lines contain space-separated three integers — ai, bi (1 ≤ ai < bi ≤ n) and ci (1 ≤ ci ≤ m). Note that there can be multiple edges between two vertices. However, there are no multiple edges of the same color between two vertices, that is, if i ≠ j, (ai, bi, ci) ≠ (aj, bj, cj).
The next line contains a integer — q (1 ≤ q ≤ 100), denoting the number of the queries.
Then follows q lines, containing space-separated two integers — ui and vi (1 ≤ ui, vi ≤ n). It is guaranteed that ui ≠ vi.
Output
For each query, print the answer in a separate line.
Sample Input
Input

4 5
1 2 1
1 2 2
2 3 1
2 3 3
2 4 3
3
1 2
3 4
1 4

Output

2
1
0

Input

5 7
1 5 1
2 5 1
3 5 1
4 5 1
1 2 2
2 3 2
3 4 2
5
1 5
5 1
2 5
1 5
1 4

Output

1
1
1
1
2

Hint
Let's consider the first sample.
 The figure above shows the first sample.

Vertex 1 and vertex 2 are connected by color 1 and 2.

Vertex 3 and vertex 4 are connected by color 3.

Vertex 1 and vertex 4 are not connected by any single color.

/*

  ：  i j       (    )   

        ，    

   i,j       dfs

*/

#include <cstdio>

#include <cstring>

#include <algorithm>

#include <vector>

using namespace std;

int map[110][110];

int vis[110];

int vis1[110][110];

int color[110][110][110];

vector<int> G[110];

int sum;



bool dfs(int u,int vv,int color1)

{

    if(!vis[u]){

        vis[u] = 1;

    if(u == vv) return true;

    for(int i = 0 ; i < G[u].size(); i++){

        int v = G[u][i];

        for(int j = 1 ; j <= vis1[u][v]; j++){

        if(color[u][v][j] == color1){

           if( dfs(v, vv, color1)) return true;

        }

        }

    }

    }

    return false ;

}



int main()

{

int n, m, k;

int a, b, c;

while(~scanf("%d %d", &n, &m)){

    memset(vis, 0, sizeof(vis1));

    for(int  i= 1; i <= m; i++){

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

        G[a].push_back(b);

        G[b].push_back(a);

        vis1[a][b]++;

        vis1[b][a]++;

        color[a][b][vis1[a][b]] = c;

        color[b][a][vis1[b][a]] = c;

    }

    scanf("%d", &k);

    int v1, v2;

    while(k--){

        sum = 0;

        scanf("%d%d", &v1, &v2);

        for(int i = 1; i <= m; i++){

            memset(vis, 0, sizeof(vis));

            if(dfs(v1, v2, i)){

                sum++;

            }

        }

        printf("%d
", sum);

    }

}

  return 0;

}