$P1195 口袋的天空$

比较有技巧的(kruskal)

#ifdef Dubug

#endif
#include <bits/stdc++.h>
using namespace std;
typedef long long LL ;
inline LL In() { LL res(0),f(1); register char c ;
	while(isspace(c=getchar())) ; c == '-'? f = -1 , c = getchar() : 0 ;
	while(res = (res << 1) + (res << 3) + (c & 15) , isdigit(c=getchar())) ;
	return res * f ;
}

const int N = 1 << 10 ;
int n , m , k ;
int ans = 0 ;
int fa[N] ;
struct node{
	int u,v,w ;
};
node a[N << 4] ;
bool cmp (node x , node y) {
	return x.w < y.w ;
}

inline int find (int x) {
	return x == fa[x] ? fa[x] : fa[x] = find(fa[x]) ;
}

inline void merge(int x,int y) {
	fa[find(x)] = find(y) ;
}

signed main() {
	n = In() , m = In() , k = In() ;
	for(register int i=1;i<=n;i++) fa[i] = i ;
	for(register int i=1;i<=m;i++) {
		a[i].u = In() , a[i].v = In() , a[i].w = In() ;
	}
	sort(a+1,a+m+1,cmp) ;
	int ans = 0 ;
	int cnt = 0 ;
	for(register int i=1;i<=m;i++) {
		if(find(a[i].u) == find(a[i].v)) continue ;
		merge(a[i].u , a[i].v) ;
		ans += a[i].w ;
		if(++ cnt == n - k) {
			return printf("%d",ans),0 ;
		}
	}
	return puts("No Answer"),0 ;
}