CodeForces - 505B C - 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 to n. 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.

题意：给出一个有向图，边分成不同的颜色，俩点间联通的边必须是同一颜色，问俩点间联通的路线有多少条。

分析：刚开始我想的是，建一个二维数组把边的颜色分别用不同的数字标记，最后遍历看每个颜色是否能联通，不过感觉太麻烦了，看别人的博客才发现可以用并查集，当时想过用并查集，但一维的标记不了那么多条边的颜色，后来才知道可以用二维的并查集，只是将一维的并查集稍微改了一下。

代码：

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
int f[110][110];
int n,m;
int getf(int v,int w)
{
    if(f[v][w]==v)
        return v;
    return f[v][w]=getf(f[v][w],w);
}

int merge(int x,int y,int z)
{
    int tx=getf(x,z);
    int ty=getf(y,z);
    if(tx!=ty)
        f[tx][z]=ty;
}
int main()
{
    int t;
    while(~scanf("%d %d",&n,&m))
    {
        int x,y,z,sum;
        for(int i=1; i<=100; i++)
            for(int j=1; j<=100; j++)
                f[i][j]=i;
        for(int i=1;i<=m;i++)
        {
            scanf("%d%d%d",&x,&y,&z);
            merge(x,y,z);
        }
        scanf("%d",&t);
        while(t--)
        {
            scanf("%d %d",&x,&y);
            sum=0;
            for(int i=1;i<=m;i++)
                if(getf(x,i)==getf(y,i))
                    sum++;
            printf("%d\n",sum);
        }
    }
    return 0;
}