Created set_matrix_zeroes.py

Author: suhanikundu

data_structures/arrays/set_matrix_zeroes.py

@@ -0,0 +1,62 @@
+"""
+Set Matrix Zeroes Algorithm
+---------------------------
+If an element in an m x n matrix is 0, set its entire row and column to 0.
+
+Explanation:
+We use the first row and first column as markers to track which rows and
+columns should be zeroed, avoiding extra space usage (O(1) space complexity).
+
+References:
+https://leetcode.com/problems/set-matrix-zeroes/
+
+Doctest:
+>>> matrix = [
+...     [1, 1, 1],
+...     [1, 0, 1],
+...     [1, 1, 1]
+... ]
+>>> set_matrix_zeroes(matrix)
+>>> matrix
+[[1, 0, 1], [0, 0, 0], [1, 0, 1]]
+"""
+
+def set_matrix_zeroes(matrix: list[list[int]]) -> None:
+    """
+    Modify the matrix in-place such that if an element is 0,
+    its entire row and column are set to 0.
+
+    :param matrix: 2D list of integers
+    :return: None (modifies matrix in-place)
+
+    Time Complexity: O(m * n)
+    Space Complexity: O(1)
+    """
+    rows = len(matrix)
+    cols = len(matrix[0])
+    col0 = 1
+
+    # Step 1: Mark rows and columns that need to be zeroed
+    for i in range(rows):
+        if matrix[i][0] == 0:
+            col0 = 0
+        for j in range(1, cols):
+            if matrix[i][j] == 0:
+                matrix[i][0] = 0
+                matrix[0][j] = 0
+
+    # Step 2: Update the inner matrix cells
+    for i in range(1, rows):
+        for j in range(1, cols):
+            if matrix[i][0] == 0 or matrix[0][j] == 0:
+                matrix[i][j] = 0
+
+    # Step 3: Handle the first row
+    if matrix[0][0] == 0:
+        for j in range(cols):
+            matrix[0][j] = 0
+
+    # Step 4: Handle the first column
+    if col0 == 0:
+        for i in range(rows):
+            matrix[i][0] = 0