| #include <bits/stdc++.h> |
|
|
| using namespace std; |
|
|
| struct UnionFind{ |
| vector <int> path, rank; |
|
|
| UnionFind(int N_){ |
| rank.assign(N_, 0); |
| path.assign(N_, 0); |
| for(int it = 0; it < N_; it++) path[it] = it; |
| }; |
|
|
| int findSet(int idx){ |
| return ( path[idx] == idx ? idx : path[idx] = findSet(path[idx]) ); |
| } |
|
|
| bool isSameSet(int idx1, int idx2){ |
| return ( findSet(idx1) == findSet(idx2) ); |
| } |
|
|
| void unionSet(int idx1, int idx2){ |
| if( isSameSet(idx1, idx2) ) return; |
| int x = findSet(idx1), y = findSet(idx2); |
| if( rank[x] > rank[y] ) path[y] = x; |
| else path[x] = y; |
| if( rank[x] == rank[y] ) rank[y]++; |
| } |
| }; |
|
|
| typedef pair <int, int> ii; |
|
|
| const int SIZE = 110; |
| int tc, n; |
| float x[SIZE], y[SIZE]; |
| vector < pair <float, ii > > EdgeList; |
|
|
| float Kruskal(){ |
| EdgeList.clear(); |
| for(int i = 0; i < n; i++) |
| for(int j = i + 1; j < n; j++) |
| EdgeList.push_back( make_pair( hypot(x[i] - x[j], y[i] - y[j]), ii(i , j) ) ) ; |
| sort(EdgeList.begin(), EdgeList.end()); |
| UnionFind UF(n); |
| float min_cost = 0, setSize = 1; |
| for(int it = 0; it < EdgeList.size(); it++){ |
| pair <float, ii > front = EdgeList[it]; |
| if( not UF.isSameSet(front.second.first, front.second.second) ) |
| min_cost += front.first, setSize++; |
| UF.unionSet(front.second.first, front.second.second); |
| if( setSize == n ) break; |
| } |
| return min_cost; |
| } |
|
|
| int main(){ |
| scanf("%d", &tc); |
| while(tc--){ |
| scanf("%d", &n); |
| for(int it = 0; it < n; it++) scanf("%f %f", x + it, y + it); |
| printf("%.2f\n", Kruskal()); |
| if(tc) putchar('\n'); |
| } |
| return(0); |
| } |
|
|
