Question

How to find all the possible rows which are permutations of a given row in a matrix with C

Answer 1

#include <stdio.h>
#include <stdlib.h>

#define COLS 5

void printPermutationRows(int matrix[][COLS], int rows, int cols, int givenrow) {
    int *set = (int *)malloc(cols * sizeof(int));
    if (set == NULL) {
        perror("Memory allocation failed");
        exit(EXIT_FAILURE);
    }
    
    for (int j = 0; j < cols; j++) {
        set[j] = matrix[givenrow][j];
    }
    
    for (int i = 0; i < rows; i++) {
        if (i == givenrow) {
            continue;
        }
        
        int j;
        for (j = 0; j < cols; j++) {
            int k;
            for (k = 0; k < cols; k++) {
                if (matrix[i][j] == set[k]) {
                    break;
                }
            }
            if (k == cols) {
                break;
            }
        }
        
        if (j != cols) {
            continue;
        }
        
        printf("%d, ", i);
    }
    
    free(set);
}

int main()
{
    int givenrow = 1;
    
    int matrix[][COLS] = {
        {7, 9, 4, 3, 1},
        {4, 7, 9, 1, 3},
        {4, 7, 8, 1, 2},
        {1, 6, 9, 7, 4},
        {9, 1, 3, 7, 4},
    };
    
    int rows = sizeof matrix / sizeof matrix[0];
    int cols = sizeof matrix[0] / sizeof(int);
    
    printPermutationRows(matrix, rows, cols, givenrow);
    
    return 0;
}


/*
run:

0, 4,  
  
*/

 

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