Cod sursa(job #1518629)

Utilizator AlexandruValeanuAlexandru Valeanu AlexandruValeanu Data 6 noiembrie 2015 00:38:28
Problema Algoritmul lui Gauss Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.65 kb
#include <bits/stdc++.h>

using namespace std;

const double EPS = 1e-10;

const int MAX_N = 300 + 2;

double A[MAX_N][MAX_N];
double solution[MAX_N];

int N, M;

int main()
{
    ifstream in("gauss.in");
    ofstream out("gauss.out");

    in >> N >> M;

    for (int i = 1; i <= N; ++i)
        for (int j = 1; j <= M + 1; ++j)
            in >> A[i][j];

    int i = 1, j = 1;

    while (i <= N && j <= M)
    {
        int k = 0;
        int p = i;

        while (p <= N)
        {
            if (fabs(A[p][j]) > EPS)
            {
                k = p;
                break;
            }

            p++;
        }

        if (!k)
        {
            j++;
            continue;
        }

        swap(A[i], A[k]);

        for (int p = j + 1; p <= M + 1; ++p)
            A[i][p] /= A[i][j];

        A[i][j] = 1.0;

        for (int l = i + 1; l <= N; ++l)
        {
            double coef = A[l][j];

            for (int c = j; c <= M + 1; ++c)
                A[l][c] -= coef * A[i][c];
        }

        i++; j++;
    }

    for (int i = N; i >= 1; i--)
    {
        int j = 1;

        while (j <= M + 1)
        {
            if (fabs(A[i][j]) > EPS)
            {
                if (j == M + 1)
                {
                    out << "Imposibil\n";
                    return 0;
                }

                solution[j] = A[i][M + 1];

                for (int k = j + 1; k <= M; ++k)
                    solution[j] -= A[i][k] * solution[k];

                break;
            }

            j++;
        }
    }

    for (int i = 1; i <= M; ++i)
        out << fixed << setprecision(8) << solution[i] << " ";

    out << endl;

    return 0;
}