Cod sursa(job #609061)

Utilizator SpiderManSimoiu Robert SpiderMan Data 19 august 2011 14:15:38
Problema Algoritmul lui Gauss Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.67 kb
# include <cstdio>

typedef long double db;
const char *FIN = "gauss.in", *FOU = "gauss.out";
const int MAX = 305;
const db eps = 1e-7;

int N, M;
db A[MAX][MAX], rez[MAX];

inline void swap (db &x, db &y) {
    db aux = x;
    x = y;
    y = aux;
}

int main (void) {
    freopen (FIN, "r", stdin);
    freopen (FOU, "w", stdout);

    scanf ("%d %d", &N, &M);
    for (int i = 1; i <= N; ++i)
        for (int j = 1, x; j <= M + 1; ++j)
            scanf ("%d", &x), A[i][j] = x;
    for (int i = 1, j = 1; i <= N && j <= M; ++i, ++j) {
        for (int k = i; k <= N; ++k) {
            if (A[k][j] < -eps || A[k][j] > eps) {
                if (k != i)
                    for (int l = 1; l <= M + 1; ++l)
                        swap (A[i][l], A[k][l]);
                break ;
            }
            if (k == N) {
                --i;
                goto etc;
            }
        }
        for (int k = j + 1; k <= M + 1; ++k)
            A[i][k] /= A[i][j];
        A[i][j] = 1.0;
        for (int k = i + 1; k <= N; A[k++][j] = 0)
            for (int l = j + 1; l <= M + 1; ++l)
                A[k][l] -= A[k][j] * A[i][l];
        etc : ;
    }
    for (int i = N; i; --i)
        for (int j = 1; j <= M + 1; ++j)
            if (A[i][j] < -eps || A[i][j] > eps) {
                if (j == M + 1) {
                    printf ("Imposibil");
                    return 0;
                }
                rez[j] = A[i][M + 1];
                for (int k = j + 1; k <= M; ++k)
                    rez[j] -= rez[k] * A[i][k];
                break;
            }
    for (int i = 1; i <= M; ++i)
        printf ("%.8Lf ", rez[i]);
}