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| 1 | +import java.util.Arrays; |
| 2 | + |
| 3 | +/** |
| 4 | + * m x n ํ๋ ฌ matrix๊ฐ ์ฃผ์ด์ง ๋, ์์๊ฐ 0์ด๋ผ๋ฉด 0์ ํฌํจํ๋ ํด๋น ์์๋ฅผ ํฌํจํ๋ ์ ์ฒด ํ๊ณผ ์ด์ |
| 5 | + * 0์ผ๋ก ์ธํ
ํ์ธ์. |
| 6 | + */ |
| 7 | +class Solution { |
| 8 | + |
| 9 | + // Follow Up : ๊ณต๊ฐ ๋ณต์ก๋ ๊ฐ์ ํ์ |
| 10 | + // mark first row and column as marker to set 0's |
| 11 | + // ์๊ฐ๋ณต์ก๋: O(m * n), ๊ณต๊ฐ๋ณต์ก๋: O(1) |
| 12 | + public void setZeroes(int[][] matrix) { |
| 13 | + |
| 14 | + boolean firstZero = false; |
| 15 | + |
| 16 | + for (int i = 0; i < matrix.length; i++) { |
| 17 | + for (int j = 0; j < matrix[0].length; j++) { |
| 18 | + if (matrix[i][j] == 0) { |
| 19 | + matrix[i][0] = 0; |
| 20 | + if (j == 0) { |
| 21 | + firstZero = true; |
| 22 | + } else { |
| 23 | + matrix[0][j] = 0; |
| 24 | + } |
| 25 | + } |
| 26 | + } |
| 27 | + } |
| 28 | + |
| 29 | + for (int i = 1; i < matrix.length; i++) { |
| 30 | + for (int j = 1; j < matrix[0].length; j++) { |
| 31 | + if (matrix[i][0] == 0 || matrix[0][j] == 0) { |
| 32 | + matrix[i][j] = 0; |
| 33 | + } |
| 34 | + } |
| 35 | + } |
| 36 | + |
| 37 | + if (matrix[0][0] == 0) { |
| 38 | + Arrays.fill(matrix[0], 0); |
| 39 | + } |
| 40 | + |
| 41 | + if (firstZero) { |
| 42 | + for (int i = 0; i < matrix.length; i++) { |
| 43 | + matrix[i][0] = 0; |
| 44 | + } |
| 45 | + } |
| 46 | + } |
| 47 | + |
| 48 | + // ์๊ฐ๋ณต์ก๋: O (m * n), ๊ณต๊ฐ๋ณต์ก๋: O(m + n) |
| 49 | + // public void setZeroes(int[][] matrix) { |
| 50 | + |
| 51 | + // // 0์ ํฌํจํ๋ ํ๊ณผ ์ด์ ์์น ์ ์ฅ |
| 52 | + // Set<Integer> rowsContainZeros = new HashSet<>(); |
| 53 | + // Set<Integer> colsContainZeros = new HashSet<>(); |
| 54 | + |
| 55 | + // for (int i = 0; i < matrix.length; i++) { |
| 56 | + // for (int j = 0; j < matrix[0].length; j++) { |
| 57 | + // if (matrix[i][j] == 0) { |
| 58 | + // rowsContainZeros.add(i); |
| 59 | + // colsContainZeros.add(j); |
| 60 | + // } |
| 61 | + // } |
| 62 | + // } |
| 63 | + |
| 64 | + // for (int row : rowsContainZeros) { |
| 65 | + // for (int j = 0; j < matrix[0].length; j++) { |
| 66 | + // matrix[row][j] = 0; |
| 67 | + // } |
| 68 | + // } |
| 69 | + |
| 70 | + // for (int col : colsContainZeros) { |
| 71 | + // for (int i = 0; i < matrix.length; i++) { |
| 72 | + // matrix[i][col] = 0; |
| 73 | + // } |
| 74 | + // } |
| 75 | + // } |
| 76 | + |
| 77 | + |
| 78 | +} |
| 79 | + |
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