Question

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

Answer 1

#include <iostream>
#include <unordered_set>

#define COLS 5

void printPermutationRows(int matrix[][COLS], int rows, int cols, int givenrow) {
    std::unordered_set<int> set;
    
    for (int j = 0; j < cols; j++) {
        set.insert(matrix[givenrow][j]);
    }
    
    for (int i = 0; i < rows; i++) {
        if (i == givenrow) {
            continue;
        }
        int j;
        for (j = 0; j < cols; j++) {
            if (set.find(matrix[i][j]) == set.end()) {
                break;
            }
        }
        if (j != cols) {
            continue;
        }
            
        std::cout << i << ", ";
    }
}

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);
}



/*
run:

0, 4, 
  
*/

 

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