Cod sursa(job #1147696)

Utilizator Impaler_009Mihai Nitu Impaler_009 Data 20 martie 2014 07:35:49
Problema Algoritmul lui Gauss Scor 90
Compilator cpp Status done
Runda Arhiva educationala Marime 1.67 kb
#include <fstream>
#include <iomanip>
#include <cmath>

#define maxn 301
#define eps 1e-10

using namespace std;

ifstream fin("gauss.in");
ofstream fout("gauss.out");

int n,m,fix[maxn];
double a[maxn][maxn],b[maxn],val[maxn];

int main()
{
    fin>>n>>m;

    for (int i=1; i<=n; ++i)
    {
        for (int j=1; j<=m; ++j)
        {
            fin>>a[i][j];
        }
        fin>>b[i];
    }

    int i = 1, j = 1;

    while (i <= n && j <= m)
    {
        int ok=0;

        for (int ii=i; ii<=n; ++ii)
        if (a[ii][j])
        {
            swap (a[i],a[ii]);
            swap (b[i],b[ii]);
            ok=1;
            break;
        }

        if (!ok)
        {
            ++j;
            continue;
        }
        fix[i] = j;

        for (int jj=j+1; jj<=m; ++jj)
        {
            a[i][jj] /= a[i][j];
        }
        b[i] /= a[i][j];
        a[i][j] = 1;

        for (int ii = i+1; ii <= n; ++ii)
        {
            for (int jj = j+1; jj <= m; ++jj)
            {
                a[ii][jj] -= (a[ii][j]*a[i][jj]);
            }
            b[ii] -= a[ii][j]*b[i];
            a[ii][j] = 0;
        }

        ++i; ++j;
    }

    for (i = n; i >= 1; --i)
    {
        if (!fix[i])
        {
            if (b[i])
            {
                fout<<"Imposibil";
                return 0;
            }
            continue;
        }
        int j = fix[i];

        val[j] = b[i];

        for (int k=i-1; k>=1; --k)
        {
            b[k] -= (a[k][j]*b[i]);
        }
    }

    for (int i=1; i<=m; ++i)
    {
        fout<<fixed<<setprecision(10)<<val[i]<<" ";
    }
}