B

//#include<bits/stdc++.h>//#pragma comment(linker, "/STACK:1024000000,1024000000") #include<stdio.h>#include<algorithm>#include<queue>#include<string.h>#include<iostream>#include<math.h>#include<set>#include<map>#include<vector>#include<iomanip>using namespace std;#define ll long long#define pb push_backconst int maxn=4e4+9;int n,m,root;struct EDGE{int v;int d;};vector<EDGE>G[maxn];int vs[maxn*2-1];//每次访问到的节点int dep[maxn*2-1];//节点深度int id[maxn];//编号节点第一次访问的时间void addedge(int u,int v,int d){G[u].pb((EDGE){v,d});G[v].pb((EDGE){u,d});}void dfs(int u,int fa,int d,int &k){id[u]=++k;vs[k]=u;dep[k]=d;int sz=G[u].size();for(int i=0;i<sz;i++){EDGE &e=G[u][i];if(e.v==fa)continue;dfs(e.v,u,d+e.d,k);vs[++k]=u;dep[k]=d;}}void init_dfs(){int k=0;dfs(root,-1,0,k);}int dp[maxn<<1][20];int mm[maxn<<1];void init_rmq(int n,int dep[]){mm[0]=-1;for(int i=1;i<=n;i++){mm[i]=((i&(i-1))==0)?mm[i-1]+1:mm[i-1];dp[i][0]=i;}for(int j=1;j<=mm[n];j++){for(int i=1;i+(1<<j)-1<=n;i++){if(dep[dp[i][j-1]]<dep[dp[i+(1<<(j-1))][j-1]])dp[i][j]=dp[i][j-1];else dp[i][j]=dp[i+(1<<(j-1))][j-1];}}}int rmq(int l,int r){if(l>r)swap(l,r);int k=mm[r-l+1];return dep[dp[l][k]]<=dep[dp[r-(1<<k)+1][k]]?dp[l][k]:dp[r-(1<<k)+1][k];}int lca(int u,int v){return vs[rmq(id[u],id[v])];}int main(){int n,m;while(~scanf("%d%d",&n,&m)){for(int i=1;i<=n;i++)G[i].clear();int u,v,w;char op[3];for(int i=1;i<=m;i++){scanf("%d%d%d%s",&u,&v,&w,op);addedge(u,v,w);}root=1;init_dfs();init_rmq(n*2-1,dep);int q;scanf("%d",&q);while(q--){int u,v;scanf("%d%d",&u,&v);printf("%d\n",dep[id[u]]+dep[id[v]]-2*dep[id[lca(u,v)]]);}}}

接口统一之后果然好多了