【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 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 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！