【种类并查集】codeforces 505B Mr. Kitayuta's Colorful Graph

B. Mr. Kitayuta's Colorful Graph

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

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.

Examples

input

4 51 2 11 2 22 3 12 3 32 4 331 23 41 4

output

210

input

5 71 5 12 5 13 5 14 5 11 2 22 3 23 4 251 55 12 51 51 4

output

11112

Note

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.

题意：给出n个点与m条边，每条边对应有颜色；然后给出q条询问，每个询问给出两个点，问这两个点有几种颜色相连，比如1,4就没有，因为不是相             同的颜色，题目要求必须是一种颜色贯穿相连。听说要用并查集我才会做，不过也可以使用dp或者爆搜；

思路：种类并查集的思路，以各个颜色为不同的种类，开N个并查集；因为数据很小，N才到100，所以完全可以用并查集！

代码：

#include<cstdio>#include<cstring>#include<algorithm>#include<iostream>using namespace std;const int N=100;int pre[N*100+10],Rank[N*100+10];void init(){    for(int i=0;i<N*100+10;i++)        pre[i]=i,Rank[i]=0;}int Find(int x){    int r=x;    while(pre[r]!=r)        r=pre[r];    int i=x,j;    while(i!=r)    {        j=pre[i];        pre[i]=r;        i=j;    }    return r;}void unite(int x,int y){    x=Find(x),y=Find(y);    if(x==y)  return ;    if(Rank[x]<Rank[y])        pre[x]=y;    else    {        pre[y]=x;        if(Rank[x]==Rank[y])            Rank[x]++;    }}bool same(int x,int y){    return Find(x)==Find(y);}int main(){    int n,m,T;    int u,v,c;    init();    scanf("%d%d",&n,&m);    for(int i=0;i<m;i++)    {        scanf("%d%d%d",&u,&v,&c);        unite(u+(c-1)*N,v+(c-1)*N);    }    scanf("%d",&T);    for(int i=0;i<T;i++)    {        int ans=0;        scanf("%d%d",&u,&v);        for(int i=0;i<N;i++)        {            if(same(u+i*N,v+i*N))            {//                printf("\n");//                cout<<u+i*N<<" "<<v+i*N<<endl;//                printf("\n");                ans++;            }        }        printf("%d\n",ans);    }    return 0;}

ok！

ok！