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Deven
63 lines
2.3 KiB
Python
63 lines
2.3 KiB
Python
class Solution:
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def setZeroes(self, matrix: List[List[int]]) -> None:
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"""
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Do not return anything, modify matrix in-place instead.
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"""
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# Total complexities:
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# O(mn) time
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# O(1) space
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# Prepare first row/col for marking
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firstEntry = matrix[0][0]
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# - use m[0][0] as indicator for first row and col
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NO_ZEROES_IN_FIRST_ROW_OR_COL = 1
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ZERO_IN_FIRST_ROW = 2
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ZERO_IN_FIRST_COL = 3
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ZERO_IN_FIRST_ROW_AND_COL = 4
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matrix[0][0] = NO_ZEROES_IN_FIRST_ROW_OR_COL
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if firstEntry == 0:
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matrix[0][0] = ZERO_IN_FIRST_ROW_AND_COL
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else:
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print(f"cp0")
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# Search first col for 0s - O(n)
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for i in range(1, len(matrix)):
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print(f"cp1")
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if matrix[i][0] == 0:
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matrix[0][0] = ZERO_IN_FIRST_COL
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break
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# Search first row for 0s - O(m)
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for j in range(1, len(matrix[0])):
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if matrix[0][j] == 0:
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if matrix[0][0] == ZERO_IN_FIRST_COL:
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matrix[0][0] = ZERO_IN_FIRST_ROW_AND_COL
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else:
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matrix[0][0] = ZERO_IN_FIRST_ROW
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break
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# Find all zeros outside the first row/col - O(mn)
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for i in range(1, len(matrix)):
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for j in range(1, len(matrix[i])):
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if matrix[i][j] == 0:
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# Use the first row/col as markers
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matrix[i][0] = 0
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matrix[0][j] = 0
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# Zero center as needed - O(mn)
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for i in range(1, len(matrix)):
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for j in range(1, len(matrix[i])):
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if matrix[i][0] == 0 or matrix[0][j] == 0:
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matrix[i][j] = 0
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# Set first row/col if needed
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if matrix[0][0] == ZERO_IN_FIRST_ROW or matrix[0][0] == ZERO_IN_FIRST_ROW_AND_COL:
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for j in range(1, len(matrix[0])):
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matrix[0][j] = 0
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if matrix[0][0] == ZERO_IN_FIRST_COL or matrix[0][0] == ZERO_IN_FIRST_ROW_AND_COL:
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for i in range(1, len(matrix)):
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matrix[i][0] = 0
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matrix[0][0] = firstEntry if matrix[0][0] == NO_ZEROES_IN_FIRST_ROW_OR_COL else 0 |