J - Graph and Cycles（图论/思维）

题目链接：https://codeforces.com/gym/102392/problem/J
题解&代码：https://blog.csdn.net/z472421519/article/details/103003199

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#define MAXN 1000005
typedef long long ll;
using namespace std;

ll ans=0;
bool vis[MAXN*2];
int tot,n,st;
struct Edge1 {
	int u,v;
	ll w;
}e[MAXN*2];
struct Edge {
	int to,next;
	ll w;
}edge[MAXN*2];
int head[MAXN];
void init() {
	tot=0;
	memset(head,-1,sizeof(head));
	memset(vis,false,sizeof(vis));
}
void addedge(int u, int v, int w) {
	edge[tot].to=v;
	edge[tot].w=w;
	edge[tot].next=head[u];
	head[u]=tot++;
}
bool cmp(Edge1 e1, Edge1 e2) {
	return e1.w<e2.w;
}
int main() {
	init();
	scanf("%d",&n);
	for (int i=1;i<=n*(n-1)/2;i++) {
		scanf("%d%d%lld",&e[i].u,&e[i].v,&e[i].w);
	}
	sort(e+1,e+1+n*(n-1)/2,cmp);
	for (int i=1;i<=n*(n-1)/2;i++) {
		addedge(e[i].u,e[i].v,e[i].w);
		addedge(e[i].v,e[i].u,e[i].w);
	}
	for (int i=1;i<=n;i++) {
		for(int j = head[i];~j;j=edge[j].next)
		{
			ans += edge[j].w;
			j = edge[j].next;
		}
	}
	cout << ans << endl;
	return 0;
}