1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #include <cmath>
 5 #define MAX 40002
 6 using namespace std;
 7 
 8 typedef struct{
 9     int from,to,next,l;
10 }Edge;
11 
12 Edge e[MAX<<1];
13 int p[MAX],fa[MAX],tot;  //fa:保存当前点的父亲是谁
14 int r[MAX<<1],all;          //r保存先序遍历的序列
15 int d[MAX];                    //d保存每个点的深度
16 int dp[MAX<<1][30],len[MAX];         //len保存当前点回到父亲节点的路劲长度
17 int vis[MAX];                 //保存第一次出现在r[]里面的位置
18 
19 inline void add(int u,int v,int l){
20     e[tot].from=u; e[tot].to=v;    e[tot].l=l;     e[tot].next=p[u];   p[u]=tot++;
21 }
22 
23 void dfs(int u,int par,int dep,int l){
24     d[u]=dep;
25     fa[u]=par;
26     vis[u]=all;
27     r[all++]=u;
28     len[u]=l;
29     for(int i=p[u];i!=-1;i=e[i].next){
30         if(vis[e[i].to]==-1){
31             dfs(e[i].to,u,dep+1,e[i].l);
32             r[all++]=u;
33         }
34     }
35 }
36 
37 void rmq(){
38     for(int i=0;i<all;i++) dp[i][0]=d[r[i]];
39     for(int j=1;(1<<j)<=all;j++){
40         for(int i=0;i+(1<<j)-1<all;i++){
41             dp[i][j]=min(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
42         }
43     }
44 }
45 
46 int query(int x,int y){
47     x = vis[x];
48     y = vis[y];
49     if(x>y) swap(x,y);
50     int minn,k;
51     k = log(y-x+1.0) / log(2.0);
52     minn=min(dp[x][k],dp[y-(1<<k)+1][k]);
53     return minn;
54 }
55 
56 int dist(int x,int pxy){
57     int sum=0;
58     while(d[x]!=pxy){
59         sum+=len[x];
60         x = fa[x];
61     }
62     return sum;
63 }
64 
65 int main()
66 {
67     int t,n,m,x,y,l,pxy,sum;
68     //freopen("data.txt","r",stdin);
69     scanf("%d",&t);
70     while(t--){
71         scanf("%d %d",&n,&m);
72         tot=0;
73         memset(p,-1,sizeof(p));
74         for(int i=1;i<n;i++){
75             scanf("%d %d %d",&x,&y,&l);
76             add(x,y,l);
77             add(y,x,l);
78         }
79         all=0;
80         memset(vis,-1,sizeof(vis));
81         dfs(1,1,1,0);
82         rmq();
83         while(m--){
84             scanf("%d %d",&x,&y);
85             pxy = query(x,y);
86             sum = dist(x,pxy) + dist(y,pxy);
87             printf("%d\n",sum);
88         }
89     }
90     return 0;
91 }