- Blogathon, Blogathon-2021, Geometric, Linked List, Mathematical, Matrix, square-rectangle

Form a Rectangle from boundary elements of Matrix using Linked List

class Node:          def __init__(self, val):        self.data = val        self.next = None        self.prev = None        self.top = None        self.bottom = None    class LinkedList:          def __init__(self):        self.head = None              def Quad(self, grid, n, m):                  self.head = Node(grid[0][0])                  temp = self.head                  i = 0        j = 1                  while temp.top != self.head:                                                                                      if j < m and i == 0:                temp.next = Node(grid[i][j])                temp = temp.next                j += 1                                      elif j == m and i < n - 1:                i = i + 1                temp.bottom = Node(grid[i][j - 1])                temp = temp.bottom                                      elif i == n - 1 and j = 1:                if j == m: j = j - 1                j = j - 1                temp.prev = Node(grid[i][j])                temp = temp.prev                                      elif i