Cod sursa(job #2744252)

Utilizator FunnyStockyMihnea Andreescu FunnyStocky Data 24 aprilie 2021 10:21:14
Problema Algoritmul lui Gauss Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.7 kb
#include <cstdio>
#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

typedef long ld;
const int N = 300 + 7;
int n, m, pi[N], pj[N];
ld a[N][N], sol[N];

int main() {
  freopen ("gauss.in", "r", stdin);
  freopen ("gauss.out", "w", stdout);

  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m + 1; j++) {
      cin >> a[i][j];
    }
  }
  for (int i = 0; i < N; i++) {
    pi[i] = -1;
    pj[i] = -1;
  }
  while (1) {
    int r = -1, c = -1;
    ld mx = -1;
    for (int i = 1; i <= n; i++) {
      if (pi[i] == -1) {
        for (int j = 1; j <= m; j++) {
          if (pj[j] == -1) {
            if (fabs(a[i][j]) - mx > 1e-14) {
              mx = fabs(a[i][j]);
              r = i;
              c = j;
            }
          }
        }
      }
    }
    if (r == -1) {
      break;
    }
    ld x = a[r][c];
    for (int j = 1; j <= m + 1; j++) {
      a[r][j] /= x;
    }
    int k = r, j = c;
    pi[k] = j;
    pj[j] = k;
    for (int i = 1; i <= n; i++) {
      if (i != k && fabs(a[i][j]) > 1e-14) {
        ld coef = a[i][j] / a[k][j];
        for (int col = 1; col <= m + 1; col++) {
          a[i][col] -= coef * a[k][col];
        }
      }
    }
  }
  for (int i = 1; i <= n; i++) {
    if (pi[i] != -1) {
      sol[pi[i]] = a[i][m + 1];
    }
  }
  for (int i = 1; i <= n; i++) {
    ld sum = 0;
    for (int j = 1; j <= m; j++) {
      sum += sol[j] * a[i][j];
    }
    if (fabs(sum - a[i][m + 1]) > 1e-14) {
      cout << "Imposibil\n";
      return 0;
    }
  }
  for (int j = 1; j <= m; j++) {
    cout << fixed << setprecision(10) << sol[j] << " ";
  }
  cout << "\n";
  return 0;
}