Cod sursa(job #2188068)

Utilizator MaligMamaliga cu smantana Malig Data 26 martie 2018 21:58:54
Problema Algoritmul lui Gauss Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.3 kb
#include <bits/stdc++.h>

using namespace std;

#if 1
    #define pv(x) cout<<#x<<" = "<<x<<"; ";cout.flush()
    #define pn cout<<endl
#else
    #define pv(x)
    #define pn
#endif

#ifdef ONLINE_JUDGE
    #define in cin
    #define out cout
#else
    ifstream in("gauss.in");
    ofstream out("gauss.out");
#endif

using ll = long long;
using ull = unsigned long long;
using uint = unsigned int;
#define pb push_back
#define mp make_pair
const int NMax = 3e6 + 5;
const ll inf_ll = 1e18 + 5;
const int inf_int = 1e9 + 5;
const int mod = 100003;
const double eps = 1e-7;
using zint = int;

int main() {
    FILE *out = fopen("gauss.out","w");
    int N,M;
    in >> N >> M;

    vector< vector<double> > a(N+1);
    for (int i = 1;i <= N;++i) {
        a[i] = vector<double>(M + 2);
        for (int j = 1;j <= M+1;++j) {
            in >> a[i][j];
        }
    }

    int i = 1, j = 1;
    while (i <= N && j <= M) {
        int k = i;
        while (k <= N && -eps < a[k][j] && a[k][j] < eps) {
            ++k;
        }

        if (k == N+1) {
            ++j;
            continue;
        }

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

        for (int u = j+1;u <= M+1;++u) {
            a[i][u] /= a[i][j];
        }
        a[i][j] = 1;

        for (int k = i+1;k <= N;++k) {
            for (int u = j+1;u <= M+1;++u) {
                a[k][u] -= a[i][u] * a[k][j];
            }
            a[k][j] = 0;
        }

        ++i;++j;

        /*
        for (int c1 = 1;c1 <= N;++c1) {
            for (int c2 = 1;c2 <= M+1;++c2) {
                printf("%-3.4f ",a[c1][c2]);
            }
            pn;
        }
        pn;
        //*/
    }

    vector< double > X(M+1,0.0);
    for (int i = N;i > 0;--i) {
        int k;
        for (k = 1;k <= M+1;++k) {
            if (a[i][k] < -eps || eps < a[i][k]) {
                break;
            }
        }

        if (k == M+2) {
            continue;
        }

        if (k == M+1) {
            fprintf(out,"Imposibil");
            return 0;
        }

        X[k] = a[i][M+1];
        for (int j = k+1;j < M+1;++j) {
            X[k] -= a[i][j] * X[j];
        }
    }

    for (int i = 1;i <= M;++i) {
        fprintf(out,"%.10f ",X[i]);
    }

    fclose(out);
    return 0;
}