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OI-codes/Hydro/system/H1004/H1004.cpp

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#include <bits/stdc++.h>
using namespace std;
int n, m, fa[100005], cnt;
long long res;
struct node {
int u, v;
long long w;
bool operator<(const node x) const {
return w < x.w;
}
} g[200005];
int find(int x) {
return fa[x] = fa[x] != x ? find(fa[x]) : fa[x];
}
int main() {
cin >> n >> m;
for (int i = 0; i < m; i++) {
cin >> g[i].u >> g[i].v >> g[i].w;
}
sort(g, g + m);
for (int i = 1; i <= n; i++) {
fa[i] = i;
}
for (int i = 0; i < m; i++) {
g[i].u = find(g[i].u);
g[i].v = find(g[i].v);
if (g[i].u != g[i].v) {
fa[g[i].u] = g[i].v;
res += g[i].w;
cnt++;
}
}
cout << res << endl;
return 0;
}