#include<bits/stdc++.h>
using namespace std;
const int N = 5010;
const int M = 2e5 + 10;
struct Node {
int a, b, c;
}e[M];
int vis[M];
int p[N], bst[N];
int n, m;
int find(int x) {
if(x != p[x]) p[x] = find(p[x]);
return p[x];
}
bool Better(int x, int y) {
if(!y) return true;
if(e[x].c == e[y].c) return x < y;
return e[x].c < e[y].c;
}
int main()
{
scanf("%d%d", &n, &m);
for(int i = 1; i <= m; ++i) scanf("%d%d%d", &e[i].a, &e[i].b, &e[i].c);
for(int i = 1; i <= n; ++i) p[i] = i;
int cnt = 0, sum = 0;
int update = 1;
while(update) {
update = 0;
memset(bst, 0, (n + 1) * sizeof(int));
for(int i = 1; i <= m; ++i) {
if(vis[i]) continue;
int a = find(e[i].a), b = find(e[i].b);
if(a == b) continue;
if(Better(i, bst[a])) bst[a] = i;
if(Better(i, bst[b])) bst[b] = i;
}
for(int i = 1; i <= n; ++i)
if(bst[i] && !vis[bst[i]]) {
update = 1;
++cnt;
sum += e[bst[i]].c;
vis[bst[i]] = 1;
p[find(e[bst[i]].a)] = find(e[bst[i]].b);
}
}
if(cnt == n - 1) printf("%d\n", sum);
else puts("orz");
return 0;
}
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转载自blog.csdn.net/weixin_43900869/article/details/109387021
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