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#include <bits/stdc++.h>
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using namespace std;
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int parent[200];
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float getDist(pair<int, int> p1, pair<int, int> p2){
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float x = p1.first - p2.first, y = p1.second - p2.second;
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return sqrt(x*x + y*y);
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}
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int cmp(const pair<float, pair<int, int> >& p1, const pair<float, pair<int, int> >& p2){
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return p1.first < p2.first;
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}
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void makeSet(int n){
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for(int i = 0; i < n; i++) parent[i] = i;
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}
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int find(int i){
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if(i == parent[i]) return i;
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return find(parent[i]);
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}
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bool sameSet(int i, int j){
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return find(i) == find(j);
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}
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void unionSet(int i, int j){
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int iRoot = find(i), jRoot = find(j);
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parent[iRoot] = jRoot;
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}
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int main(){
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int n, tc;
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float x, y;
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vector<pair<float, float> > points;
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vector<pair<float, pair<int, int> > > edges;
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vector<pair<float, pair<int, int> > > kruskal;
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scanf("%d", &tc);
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while(tc--){
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scanf("%d", &n);
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points.clear();
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edges.clear();
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kruskal.clear();
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makeSet(n);
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for(int i = 0; i < n; i++) scanf("%f %f", &x, &y), points.push_back(make_pair(x, y));
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for(int i = 0; i < n; i++){
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for(int j = i + 1; j < n; j++){
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float w = getDist(points[i], points[j]);
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pair<int, int> nodes = make_pair(i, j);
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edges.push_back(make_pair(w, nodes));
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}
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}
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sort(edges.begin(), edges.end(), cmp);
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for(int i = 0; i < edges.size(); i++){
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int nodeI = edges[i].second.first, nodeJ = edges[i].second.second;
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if(!sameSet(nodeI, nodeJ)){
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kruskal.push_back(edges[i]);
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unionSet(nodeI, nodeJ);
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}
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}
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float total = 0;
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for(int i = 0; i < kruskal.size(); i++) total+=kruskal[i].first;
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printf("%.2f\n", total);
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if(tc) printf("\n");
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}
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return 0;
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}
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