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E.cpp
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E.cpp
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#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define ff first
#define ss second
#define rep(i, a, b) for(int i = a; i < b; i++)
#define repR(i, a, b) for (int i = a; i >= b; --i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()
#define mem1(a) memset(a,-1,sizeof(a))
#define mem0(a) memset(a,0,sizeof(a))
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define vi vector<int>
#define vvi vector<vi>
#define vll vector<ll>
#define vvll vector<vll>
#define vs vector<string>
#define vb vector<bool>
#define vpii vector<pii>
#define vpll vector<pll>
#define mod 1000000007
#define ps(x,y) fixed << setprecision(y) << x
#define fastio ios_base::sync_with_stdio(false),cin.tie(NULL),cout.tie(NULL)
const int MaxN = 2e5 + 10;
int n, m;
struct Edge {
int u, v, w;
};
Edge edges[MaxN];
int p[MaxN], r[MaxN];
void init()
{
rep(i, 0, MaxN) {
p[i] = i;
r[i] = 1;
}
}
int find_set(int x)
{
if (p[x] == x) {
return x;
}
return p[x] = find_set(p[x]);
}
void union_set(int a, int b)
{
a = find_set(a);
b = find_set(b);
if (a != b) {
if (r[a] < r[b])
swap(a, b);
}
p[b] = p[a];
r[a] += r[b];
}
void addEdge(Edge &e, int u, int v, int w)
{
e.u = u, e.v = v, e.w = w;
}
bool comp(Edge &e1, Edge &e2)
{
return e1.w < e2.w;
}
ll KruskalMST()
{
sort(edges, edges + m, comp);
ll reward = 0;
rep(i, 0, m) {
int u = edges[i].u, v = edges[i].v, w = edges[i].w;
u = find_set(u);
v = find_set(v);
if (u != v) {
union_set(u, v);
}
else if (w > 0) {
reward += w;
}
}
return reward;
}
void solve()
{
cin >> n >> m;
rep(i, 0, m) {
int u, v, w;
cin >> u >> v >> w;
addEdge(edges[i], u, v, w);
}
cout << KruskalMST() << '\n';
}
int main()
{
fastio;
/*#ifndef ONLINE_JUDGE
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
#endif*/
init();
int t = 1;
//cin>>t;
while (t--) solve();
return 0;
}