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OI-codes/Luogu/P1967/P1967.cpp

68 lines
1.5 KiB
C++

#include <bits/stdc++.h>
using namespace std;
int n, m, q, x, y, c, px, py, ans[50005], fa[10005];
set<int> f[10005];
set<int>::iterator it;
struct edge {
int u, v, cost;
bool operator<(edge b) {
return cost > b.cost;
}
} es[50005];
int find(int x) {
return x == fa[x] ? x : fa[x] = find(fa[x]);
}
int main() {
memset(ans, 0xff, sizeof(ans));
for (int i = 1; i < 10005; i++) {
fa[i] = i;
}
cin >> n >> m;
for (int i = 0; i < m; i++) {
cin >> es[i].u >> es[i].v >> es[i].cost;
}
sort(es, es + m);
cin >> q;
for (int i = 0; i < q; i++) {
cin >> x >> y;
f[x].insert(i);
f[y].insert(i);
}
for (int i = 0; i < m; i++) {
x = es[i].u;
y = es[i].v;
c = es[i].cost;
px = find(x);
py = find(y);
if (px == py) {
continue;
} else {
if (f[px].size() > f[py].size()) {
swap(px, py);
}
vector<int> tmp;
for (it = f[px].begin(); it != f[px].end(); it++) {
if (f[py].count(*it)) {
ans[*it] = c;
tmp.push_back(*it);
}
f[py].insert(*it);
}
for (int i = 0; i < tmp.size(); i++) {
f[py].erase(tmp[i]);
}
fa[px] = py;
}
}
for (int i = 0; i < q; i++) {
cout << ans[i] << endl;
}
return 0;
}