洛谷 P4035

#include <bits/stdc++.h>

using namespace std;

const int N = 250;
int n;
double a[N][N], x[N], p[N][N], q[N][N];

void gauss()
{
  for (int i = 1; i <= n; i ++)
  {
    for (int j = i; j <= n; j ++)
      if (a[j][i])
      {
        for (int k = 1; k <= n + 1; k ++)
          swap (a[i][k], a[j][k]);
        break;
      }
    if (a[i][i] == 0)
    {
      cout << "No Solution\n";
      exit(1);
    }
    for (int j = i + 1; j <= n; j ++)
    {
      double ratio = a[j][i] / a[i][i];
      for (int k = 1; k <= n + 1; k ++)
        a[j][k] -= a[i][k] * ratio;
    }
  }
  x[n] = a[n][n + 1] / a[n][n];
  for (int i = n; i; i --)
  {
    for (int j = i + 1; j <= n; j ++)
      a[i][n + 1] -= a[i][j] * x[j];
    x[i] = a[i][n + 1] / a[i][i];
  }
}

signed main()
{
  cin >> n;
  for (int i = 1; i <= n + 1; i ++)
    for (int j = 1; j <= n; j ++)
      cin >> p[i][j];
  for (int i = 1; i <= n; i ++)
    for (int j = 1; j <= n; j ++)
    {
      a[i][j] = 2 * (p[i][j] - p[i + 1][j]);
      a[i][n + 1] += p[i][j] * p[i][j] - p[i + 1][j] * p[i + 1][j];
    }
  gauss();
  for (int i = 1; i <= n; i ++)
    printf ("%.3lf%c", x[i], " \n"[i == n]);
  return 0;
}