diff --git a/src/9/2/P1967.cpp b/src/9/2/P1967.cpp
index 21ae23b..0a13100 100644
--- a/src/9/2/P1967.cpp
+++ b/src/9/2/P1967.cpp
@@ -1,9 +1,11 @@
+#include <algorithm>
 #include <cstdint>
 #include <cstdio>
 #include <cstring>
 #include <ios>
 #include <iostream>
 #include <queue>
+#include <utility>
 #include <vector>
 
 using ll = int64_t;
@@ -23,9 +25,11 @@ struct XYZ{
     }
 };
 
-ll n,m;
+const ll maxlog = 15, inf=1e9;
+ll n,m,q;
 std::vector<std::vector<Edge>> edg;
-std::vector<ll> unf;
+std::vector<ll> unf, dpth;
+std::vector<std::vector<ll>> fth,cost;
 std::priority_queue<XYZ> pq;
 ll mergednum = 0;
 
@@ -42,6 +46,42 @@ static inline bool ismerged(ll a,ll b){
     return find(a)==find(b);
 }
 
+static inline void dfs(ll f,ll cur){
+    dpth[cur]=dpth[f]+1;
+    fth[cur][0]=f;
+    for(ll i=1;i<=maxlog;i++){
+        fth[cur][i]=fth[fth[cur][i-1]][i-1];
+        cost[cur][i]=std::min(cost[fth[cur][i-1]][i-1],cost[cur][i-1]);
+    }
+    for(auto nxt:edg[cur]){
+        if(nxt.to==f)continue;
+        cost[nxt.to][0]=nxt.w;
+        dfs(cur,nxt.to);
+    }
+}
+
+static inline ll lca(ll a,ll b){
+    if(dpth[a]>dpth[b])std::swap(a,b);
+    // ll tmp = dpth[b]-dpth[1],ans=0;错误
+    ll tmp = dpth[b]-dpth[a],ans=inf;
+    for(ll j=0;tmp;j++,tmp>>=1){
+        if(tmp&1){
+            ans=std::min(ans,cost[b][j]);
+            b=fth[b][j]; // 注意在if里面
+        }
+    }
+    if(a==b)return ans;
+    for(ll j=maxlog;j>=0 && a!=b;j--){
+        if(fth[a][j]!=fth[b][j]){
+            ans=std::min({ans,cost[a][j],cost[b][j]});
+            a=fth[a][j];
+            b=fth[b][j];
+        }
+    }
+    ans=std::min({ans,cost[a][0],cost[b][0]});
+    return ans;
+}   
+
 int main(){
     std::ios_base::sync_with_stdio(false);
     std::cin.tie(nullptr);
@@ -50,8 +90,15 @@ int main(){
 
     edg.resize(n+1);
     unf.resize(n+1);
+    fth.resize(n+1,std::vector<ll>(maxlog+1));
+    cost.resize(n+1,std::vector<ll>(maxlog+1,inf));
+    dpth.resize(n+1);
 
     for(ll i=1;i<=n;i++){
+        unf[i]=i;
+    }
+
+    for(ll i=1;i<=m;i++){
         ll x,y,z;
         std::cin>>x>>y>>z;
         pq.emplace(x,y,z);
@@ -67,12 +114,26 @@ int main(){
         mergednum++;
     }
 
-    for(ll u=1;u<=n;u++){
-        for(auto [v,w]:edg[u]){
-            char buff[128];
-            memset(buff, 0, sizeof(buff));
-            sprintf(buff,"point %lld to %lld weight %lld\n",u,v,w);
-            std::cout<<buff;
+    // for(ll u=1;u<=n;u++){
+    //     for(auto [v,w]:edg[u]){
+    //         printf("point %lld to %lld weight %lld\n",u,v,w);
+    //     }
+    // }
+
+    for(ll i=1;i<=n;i++){
+        if(dpth[i]==0){
+            dpth[0]=0;
+            dfs(0,i);
         }
     }
+    std::cin>>q;
+    for(ll i=1;i<=q;i++){
+        ll a,b;
+        std::cin>>a>>b;
+        if (!ismerged(a, b)) {
+            std::cout<<"-1\n";
+            continue;
+        }
+        std::cout<<lca(a,b)<<'\n';
+    }
 }
\ No newline at end of file