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Time: 3 ms (71.33%), Space: 18.6 MB (17.59%) - LeetHub

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Deven
2025-11-26 14:30:06 -05:00
parent 3399d5f921
commit afdd2ae59f
1 changed files with 52 additions and 14 deletions
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0073-set-matrix-zeroes/0073-set-matrix-zeroes.py
+52 -14
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@@ -5,21 +5,59 @@ class Solution:
""" """
# Total complexities: # Total complexities:
# O(mn) time # O(mn) time
# O(m+n) space # O(1) space
# O(m+n) space # Prepare first row/col for marking
rowsToZero = set() firstEntry = matrix[0][0]
colsToZero = set() # - use m[0][0] as indicator for first row and col
NO_ZEROES_IN_FIRST_ROW_OR_COL = 1
ZERO_IN_FIRST_ROW = 2
ZERO_IN_FIRST_COL = 3
ZERO_IN_FIRST_ROW_AND_COL = 4
# Find all zeros - O(mn) matrix[0][0] = NO_ZEROES_IN_FIRST_ROW_OR_COL
for i in range(len(matrix)): if firstEntry == 0:
for j in range(len(matrix[i])): matrix[0][0] = ZERO_IN_FIRST_ROW_AND_COL
else:
print(f"cp0")
# Search first col for 0s - O(n)
for i in range(1, len(matrix)):
print(f"cp1")
if matrix[i][0] == 0:
matrix[0][0] = ZERO_IN_FIRST_COL
break
# Search first row for 0s - O(m)
for j in range(1, len(matrix[0])):
if matrix[0][j] == 0:
if matrix[0][0] == ZERO_IN_FIRST_COL:
matrix[0][0] = ZERO_IN_FIRST_ROW_AND_COL
else:
matrix[0][0] = ZERO_IN_FIRST_ROW
break
# Find all zeros outside the first row/col - O(mn)
for i in range(1, len(matrix)):
for j in range(1, len(matrix[i])):
if matrix[i][j] == 0: if matrix[i][j] == 0:
rowsToZero.add(i) # Use the first row/col as markers
colsToZero.add(j) matrix[i][0] = 0
matrix[0][j] = 0
# Zero rows and cols as needed - O(mn) # Zero center as needed - O(mn)
for i in range(len(matrix)): for i in range(1, len(matrix)):
for j in range(len(matrix[i])): for j in range(1, len(matrix[i])):
if i in rowsToZero or j in colsToZero: if matrix[i][0] == 0 or matrix[0][j] == 0:
matrix[i][j] = 0 matrix[i][j] = 0
# Set first row/col if needed
if matrix[0][0] == ZERO_IN_FIRST_ROW or matrix[0][0] == ZERO_IN_FIRST_ROW_AND_COL:
for j in range(1, len(matrix[0])):
matrix[0][j] = 0
if matrix[0][0] == ZERO_IN_FIRST_COL or matrix[0][0] == ZERO_IN_FIRST_ROW_AND_COL:
for i in range(1, len(matrix)):
matrix[i][0] = 0
matrix[0][0] = firstEntry if matrix[0][0] == NO_ZEROES_IN_FIRST_ROW_OR_COL else 0