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#include <math.h> |
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#include <stdio.h> |
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#include <cstring> |
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#include <iostream> |
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#include <algorithm> |
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using namespace std; |
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double X[102], Y[102], M[102][102]; |
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double dist(int i, int j) { |
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double x = X[i] - X[j], |
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y = Y[i] - Y[j]; |
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return sqrt(x*x + y*y); |
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} |
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struct Edge { |
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int i, j; |
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double dist; |
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bool operator < (const Edge& o) const { |
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return dist < o.dist; |
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} |
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}; |
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Edge edges[102*102]; |
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bool tr[102][102]; |
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int main(){ |
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int N; |
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cin>>N; |
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while(N--) { |
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int n; |
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cin>>n; |
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for(int i=0; i<n; i++) |
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cin>>X[i]>>Y[i]; |
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int l = 0; |
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for (int i=0; i<n; i++) { |
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M[i][i] = 0; |
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tr[i][i] = true; |
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for (int j=i+1; j<n; j++) { |
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Edge& e = edges[l++]; |
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e.i=i; e.j=j; |
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e.dist = M[i][j] = M[j][i] = dist(i, j); |
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tr[i][j] = tr[j][i] = false; |
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} |
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} |
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sort(edges, edges+l); |
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int c = 0, k = 0; |
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double res = 0; |
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while (c < n-1) { |
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Edge& e = edges[k++]; |
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if (!tr[e.i][e.j]) { |
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c++; |
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res += e.dist; |
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tr[e.i][e.j] = tr[e.j][e.i] = true; |
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for (int i=0; i<n; i++) |
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if (tr[i][e.i]) |
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for (int j=0; j<n; j++) |
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if (tr[e.j][j]) |
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tr[i][j] = tr[j][i] = true; |
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} |
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} |
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printf("%.2f\n", res); |
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if (N) cout<<endl; |
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} |
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} |
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