#include <cmath>#include <cstdio>#include <algorithm>using namespace std;const int MAXN = 200;const double INF = 1e100;double x[MAXN];inline double calcdiff(int i, int j, int k){ return fabs(x[i] + (x[j] - x[i]) * (k - i) / (j - i) - x[k]);}int main(){ int t; scanf("%d", &t); while(t--){ int h, c; scanf("%d%d", &h, &c); double dp[MAXN][MAXN]; double cost[MAXN][MAXN]; for (int i = 0; i < h; i++){ scanf("%lf", &x[i]); dp[0][i] = INF; } for (int i = 0; i < h; i++) for (int j = i + 1; j < h; j++){ cost[i][j] = 0; for (int k = i + 1; k < j; k++) cost[i][j] += calcdiff(i, j, k); } dp[0][0] = 0; for (int l = 1; l < c; l++) for (int j = l; j < h; j++){ dp[l][j] = INF; for (int i = 0; i < j; i++) dp[l][j] = min(dp[l][j], dp[l - 1][i] + cost[i][j]); } printf("%.4lfn", dp[c - 1][h - 1] / h); } return 0;}
