HDU - 1233-还是畅通工程 · znzryb
## 思路讲解
[](https://www.notion.so/1454539447bd80949fb6d5b2057602f6) 无向图判环模版题
无向图判环+贪心选择短边，这就是kruskal算法
## AC代码
[https://vjudge.net/solution/57384651](https://vjudge.net/solution/57384651)
```cpp
#include <iostream>
#include <cstring>
#include <algorithm>
#include <deque>
#include <queue>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <cmath>
#include <bitset>
#include <iterator>
#include <random>
#include <iomanip>
#include <cctype>
#include <array>
typedef long long ll;
typedef std::pair<ll,ll> pll;
typedef std::array<ll,3> arr;
const ll MAXN=110;
ll fa[110];
ll N;
struct cmp{
bool operator()(arr a,arr b){
if(a[2]!=b[2])
return a[2]>b[2];
return false;
}
};
inline void init(){
for(int i=0;i<N+7;++i)
fa[i]=i;
}
inline ll find(ll x){
if(fa[x]==x)
return x;
fa[x]=find(fa[x]);
return fa[x];
}
void solve(){
init();
std::priority_queue<arr,std::vector<arr>,cmp> pq;
for(int i=1;i<=N*(N-1)/2;++i){
ll a,b,c;
std::cin>>a>>b>>c;
pq.push({a,b,c});
}
ll ans=0;
while (!pq.empty()) {
ll a=pq.top()[0],b=pq.top()[1],c=pq.top()[2];
pq.pop();
if(find(a)!=find(b)){
fa[find(a)]=find(b);
ans+=c;
}
}
std::cout<<ans<<"\n";
return;
}
int main()
{
std::ios::sync_with_stdio(false);
std::cin.tie(0);std::cout.tie(0);
while (std::cin>>N) {
if(N==0){
break;
}
solve();
}
return 0;
}
/*
AC https://vjudge.net/solution/57384651
3
1 2 1
1 3 2
2 3 4
4
1 2 1
1 3 4
1 4 1
2 3 3
2 4 2
3 4 5
0
*/
```
## 心路历程（WA，TLE，MLE……）