输出

0
-1
0

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 1e4+5, M = 5e4+5;
struct Edge{
	int u, v, w;
}edge[M];
int n, m, q;
int head[N], nxt[N << 1], to[N << 1], val[N << 1], cccnnnttt;
int anc[N][25], d[N], w[N][25];
bool vis[N];
int pa[N];
int find(int x){ return x == pa[x] ? x : pa[x] = find(pa[x]); }
void merge(int x, int y){ pa[find(x)] = find(y); }
bool cmp(Edge a, Edge b){
	return a.w > b.w;
}
void add(int u, int v, int w){
	to[++cccnnnttt] = v;
	val[cccnnnttt] = w;
	nxt[cccnnnttt] = head[u];
	head[u] = cccnnnttt;
}
void kruskal(){
	sort(edge + 1, edge + 1 + m, cmp);
	int cnt = 0;
	for (int i = 1;i <= m;i++){
		if (cnt == n - 1) break;
		int fu = find(edge[i].u), fv = find(edge[i].v);
		if (fu == fv) continue;
		pa[fu] = fv;
		//cout << edge[i].u << ' ' << edge[i].v << '\n';
		add(edge[i].u, edge[i].v, edge[i].w);
		add(edge[i].v, edge[i].u, edge[i].w);
		++cnt;
	}
}
void dfs(int u, int f){
	vis[u] = 1;
	for (int i = head[u];i;i = nxt[i]){
		int v = to[i];
		if (v != f){
			d[v] = d[u] + 1;
			anc[v][0] = u;
			w[v][0] = val[i];
			dfs(v, u);
		}
	}
}
void init(){
	for (int j = 1;j <= 20;j++){
		for (int i = 1;i <= n;i++) anc[i][j] = anc[anc[i][j - 1]][j - 1], w[i][j] = min(w[i][j - 1], w[anc[i][j - 1]][j - 1]);
	}
}
int LCA(int u, int v){
	if (d[u] < d[v]) swap(u, v);
	int res = INT_MAX;
	for (int i = 20;i >= 0;i--){
		if (d[anc[u][i]] >= d[v]) u = anc[u][i], res = min(res, w[u][i]);
	}
	if (u == v) return res;
	for (int i = 20;i >= 0;i--){
		if (anc[u][i] != anc[v][i]) u = anc[u][i], v = anc[v][i], res = min(res, min(w[u][i], w[v][i]));
	}
	res = min(res, min(w[u][0], w[v][0]));
	return res;
}
int main(){
	//ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	cin >> n >> m;
	for (int i = 1;i <= n;i++) pa[i] = i;
	for (int i = 1;i <= m;i++){
		cin >> edge[i].u >> edge[i].v >> edge[i].w;
	}
	kruskal();
	for (int i = 1;i <= n;i++){
		if (!vis[i]){
			d[i] = 1;
			dfs(i, 0);
			//anc[i][0] = i;
			w[i][0] = INT_MAX;
		}
	}
	init();
	cin >> q;
	while (q--){
		int x, y;
		cin >> x >> y;
		if (find(x) != find(y)){
			cout << "-1\n";
		}
		else cout << LCA(x, y) << '\n';
	}
	return 0;
} 
/*
4 3
1 2 4
2 3 3
3 1 1
3

*/