#include <stdio.h>
#include <stdbool.h>

#define N (100)
#define M (100)

void printMatrix(double a[][M], int n, int m)
{
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            printf("%.2lf", a[i][j]);
            if (j != m - 1)
            {
                printf(" ");
            }
        }
        printf("\n");
    }
}

bool inputMatrix(double a[][M], int n, int m)
{
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            if (scanf(" %lf", &a[i][j]) != 1)
            {
                return false;
            }
        }
    }

    return true;
}

void swapRows(double *r1s, double *r1e, double *r2s, double *r2e)
{
    while (r1s != r1e + 1)
    {
        const double temp = (*r1s);
        (*r1s) = (*r2s);
        (*r2s) = temp;

        r1s++;
        r2s++;
    }
}

void multiplyRow(double *rs, double *re, double scalar)
{
    while (rs != re + 1)
    {
        (*rs) *= scalar;

        rs++;
    }
}

void addRows(double *r1s, double *r1e, double *r2s, double *r2e, double s)
{
    while (r1s != r1e + 1)
    {
        (*r1s) += (s * (*r2s));

        r1s++;
        r2s++;
    }
}

void findLeadElement(double a[][M], int n, int m, int *r, int *c, bool *res)
{
    *res = false;
    for (int j = 0; j < m; j++)
    {
        for (int i = 0; i < n; i++)
        {
            if (a[i][j] != 0.0)
            {
                *r = i;
                *c = j;
                *res = true;
                return;
            }
        }
    }
}

void reduceRowsRandFunctionRantFunction(const int i, const int m,
    const int n, const int lead_c, double a[][M])
{
    for (int k = i + 1; k < n; k++)
    {
        double factor = -a[k][lead_c];
        if (factor != 0)
        {
            addRows(&a[k][0], &a[k][m - 1],
                    &a[i][0], &a[i][m - 1], factor);
        }
    }
}

void reduceRowsRantFunction(const int lead_r, const int lead_c, const int i,
    const int m, const int n, double a[][M])
{
    int cur_r = i + lead_r;
    if (cur_r != i)
    {
        swapRows(&a[i][0], &a[i][m - 1],
                 &a[cur_r][0], &a[cur_r][m - 1]);
    }
    double pivot_val = a[i][lead_c];
    multiplyRow(&a[i][0], &a[i][m - 1], 1.0 / pivot_val);

    reduceRowsRandFunctionRantFunction(i, m, n, lead_c, a);
}

void reduceRows(double a[][M], int n, int m)
{
    for (int i = 0; i < n; i++)
    {
        int lead_r, lead_c;
        bool found;

        findLeadElement(a + i, n - i, m, &lead_r, &lead_c, &found);

        if (!found)
        {
            break;
        }

        reduceRowsRantFunction(lead_r, lead_c, i, m, n, a);
    }
}

bool checkLengths(int n, int m, int longN, int longM)
{
    if (n > 0 && n <= longN && m > 0 && m <= longM)
    {
        return true;
    }

    return false;
}

int mainHelper(double matrix[][M], int n, int m)
{
    printf("Enter the matrix elements:\n");
    if (!inputMatrix(matrix, n, m))
    {
        printf("Invalid matrix elements.\n");
        return 1;
    }

    printf("Original Matrix:\n");
    printMatrix(matrix, n, m);

    reduceRows(matrix, n, m);

    printf("Reduced Matrix:\n");
    printMatrix(matrix, n, m);
    return 0;
}

int main()
{
    int n, m;
    double matrix[N][M];
    printf("Enter number of rows (n) and columns (m):\n");
    scanf("%d %d", &n, &m);
    if (!checkLengths(n, m, N, M))
    {
        printf("Invalid matrix size.\n");
        return 1;
    }

    return mainHelper(matrix, n, m);
}