heapq in Python to print all elements in sorted order from row and column wise sorted matrix

Given an n x n matrix, where every row and column is sorted in non-decreasing order. Print all elements of matrix in sorted order.

Examples:

Input : mat= [[10, 20, 30, 40],
              [15, 25, 35, 45],
              [27, 29, 37, 48],
              [32, 33, 39, 50]]

Output : Elements of matrix in sorted order
         [10, 15, 20, 25, 27, 29, 30, 32, 
          33, 35, 37, 39, 40, 45, 48, 50]

This problem has existing solution please refer link. We will solve this problem in python with the same approach of merging two sorted arrays using heapq module.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Function to print all elements in sorted order
# from row and column wise sorted matrix
from heapq import merge
  
def sortedMatrix(mat):
      
    # initialize result variable with first row of matrix
    result=mat[0]
  
    # now traverse through complete matrix 
    # after first row and merge each row with
    # result one by one
    # after last operation result will contain 
    # list of sorted elements of matrix
    for row in mat[1:]:
        result=list(merge(result,row))
  
    return result
  
if __name__ == "__main__":
    mat = [[10, 20, 30, 40],[15, 25, 35, 45], \
          [27, 29, 37, 48],[32, 33, 39, 50]]
    print 'Elements of matrix in sorted order'
    print sortedMatrix(mat)

chevron_right


Output:

Elements of matrix in sorted order
[10, 15, 20, 25, 27, 29, 30, 32, 33, 35, 37, 39, 40, 45, 48, 50]

This article is contributed by Shashank Mishra (Gullu). If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.



My Personal Notes arrow_drop_up


Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.