Added skeleton for solution of cci/1.8

cci/1.8.zero_matrix.py

@@ -3,13 +3,16 @@
 column are set to 0.
 '''
 
+from typing import List
+
+
 def zero_matrix(a, m, n):
-    R'''
-    My first `reasonnable` approach. Although I feel it is not good.
+    R"""
+    My first `reasonable` approach. Although I feel it is not good.
     O(M^2N + MN^2) time just for O(1) space :(. It's not good. We can make it O(MN) with O(M + N) space.
     Here, the obvious errors I nearly made were: 1. To think that once I find a zero on a row I just have to zero the remaining values: Nope, I have to circle through all of them to  zero their column
     2. I also have to zero left from a zero's row, and up from a zero's column.
-    '''
+    """
     if not a:
         return
 
@@ -74,16 +77,44 @@ def nullify_row(i):
     else:
         for j in a[0]:
             if j == 0:
-                set_origin = True # Be very careful, the column has already been set to 0,the ROW SHOULD NOT, only (0,0)
+                set_origin = True  # Be very careful, the column has already been set to 0,the ROW SHOULD NOT, only (0,0)
         for i in range(m):
             if a[i][0] == 0:
-                set_origin = True # Be very careful, the row has already been set to 0,the COLUMN SHOULD NOT, only (0,0)
+                set_origin = True  # Be very careful, the row has already been set to 0,the COLUMN SHOULD NOT, only (0,0)
 
     if set_origin:
         a[0][0] = 0
 
     return a
 
+
+def matrix_zero(a: List):
+    def zero_row(row):
+        for col in range(len(a[row])):
+            a[row][col] = 0
+
+    def zero_column(col):
+        for row in range(len(a)):
+            a[row][col] = 0
+
+    rows_to_zero = []
+    columns_to_zero = []
+    m = len(a)
+    for i in range(m):
+        n = len(a[i])
+        for j in range(n):
+            if a[i][j] == 0:
+                rows_to_zero.append(i)
+                columns_to_zero.append(j)
+
+    for r in rows_to_zero:
+        zero_row(r)
+
+    for c in columns_to_zero:
+        zero_column(c)
+
+
 a = [[1, 2, 0], [6, 5, 4], [7, 0, 9]]
-a = zero_matrix_auth(a, len(a), len(a[0]))
+# a = zero_matrix_auth(a, len(a), len(a[0]))
+matrix_zero(a)
 print(a)