Added the doctests - Contributes to #9943

Author: Priyal595

matrix/count_islands_in_matrix.py

@@ -4,12 +4,56 @@
 
 
 class Matrix:  # Public class to implement a graph
+    """
+    This public class represents the 2-Dimensional matrix to count the number of islands.
+    An island is the connected group of 1s including the top, down, right, left as well as
+    the diagonal connections.
+    
+    Example - 
+    
+    >>> matrix1 = Matrix(3, 3, [[1, 1, 0], [0, 1, 0], [1, 0, 1]])
+    >>> matrix1.count_islands()
+    1
+    >>> matrix2 = Matrix(2, 2, [[1, 1], [1, 1]])
+    >>> matrix2.count_islands()
+    1
+    
+    """
     def __init__(self, row: int, col: int, graph: list[list[bool]]) -> None:
+        """ 
+        This initialzes the matrix with the given number of rows, columns and the matrix.
+
+        Args:
+            row (int): number of rows in the matrix
+            col (int): number of columns in the matrix
+            graph (list[list[bool]]): 2-D list of 0s and 1s representing the matrix
+        """
         self.ROW = row
         self.COL = col
         self.graph = graph
 
     def is_safe(self, i: int, j: int, visited: list[list[bool]]) -> bool:
+        """
+        This checks if the current cell can be included in the current island.
+        
+        Args:
+            i (int): row index
+            j (int): column index
+            visited (list[list[bool]]): 2D list tracking the visited cells
+
+        Returns:
+            bool: True if the cell is valid and part of the island(1 for True and ) for False)
+            
+        >>> visited = [[False, False], [False, False]]
+        >>> graph = [[1, 0], [0, 1]]
+        >>> m = Matrix(2, 2, graph)
+        >>> m.is_safe(0, 0, visited)
+        1
+        
+        >>> m.is_safe(0, 1, visited)
+        0
+    
+        """
         return (
             0 <= i < self.ROW
             and 0 <= j < self.COL
@@ -18,6 +62,22 @@ def is_safe(self, i: int, j: int, visited: list[list[bool]]) -> bool:
         )
 
     def diffs(self, i: int, j: int, visited: list[list[bool]]) -> None:
+        """
+        This is the recursive function to mark all the cells visited which are connected to (i, j) indices.
+
+        Args:
+            i (int): row index
+            j (int): column index
+            visited (list[list[bool]]): 2D list tracking the visited cells
+            
+        >>> visited = [[False, False], [False, False]]
+        >>> graph = [[1, 1], [0, 1]]
+        >>> m = Matrix(2, 2, graph)
+        >>> m.diffs(0, 0, visited)
+        >>> visited
+        [[True, True], [False, True]]
+        
+        """
         # Checking all 8 elements surrounding nth element
         row_nbr = [-1, -1, -1, 0, 0, 1, 1, 1]  # Coordinate order
         col_nbr = [-1, 0, 1, -1, 1, -1, 0, 1]
@@ -27,6 +87,22 @@ def diffs(self, i: int, j: int, visited: list[list[bool]]) -> None:
                 self.diffs(i + row_nbr[k], j + col_nbr[k], visited)
 
     def count_islands(self) -> int:  # And finally, count all islands.
+        """
+        This counts all the islands in the given matrix.
+
+        Returns:
+            int: the number of islands in the given matrix.
+            
+        Example -
+        >>> mat = Matrix(1, 1, [[1]])
+        >>> mat.count_islands()
+        1
+        
+        >>> mat2 = Matrix(2, 2, [[0, 0], [0, 0]])
+        >>> mat2.count_islands()
+        0
+        
+        """
         visited = [[False for j in range(self.COL)] for i in range(self.ROW)]
         count = 0
         for i in range(self.ROW):