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2 | 2 | * // This is the BinaryMatrix's API interface.
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3 | 3 | * // You should not implement it, or speculate about its implementation
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4 | 4 | * interface BinaryMatrix {
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5 |
| - * public int get(int x, int y) {} |
| 5 | + * public int get(int row, int col) {} |
6 | 6 | * public List<Integer> dimensions {}
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7 | 7 | * };
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8 | 8 | */
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9 | 9 |
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10 | 10 | class Solution {
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11 | 11 | public int leftMostColumnWithOne(BinaryMatrix binaryMatrix) {
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12 |
| - List<Integer> dims = binaryMatrix.dimensions(); |
13 |
| - int rows = dims.get(0); |
14 |
| - int cols = dims.get(1); |
15 |
| - int minIdx = Integer.MAX_VALUE; |
16 |
| - for (int i = 0; i < rows; i++) { |
17 |
| - int idx = binarySearch(binaryMatrix, i, 0, cols - 1); |
18 |
| - if (idx != -1) { |
19 |
| - minIdx = Math.min(minIdx, idx); |
| 12 | + List<Integer> dimension = binaryMatrix.dimensions(); |
| 13 | + int numRows = dimension.get(0); |
| 14 | + int numCols = dimension.get(1); |
| 15 | + int currRow = 0; |
| 16 | + int currCol = numCols - 1; |
| 17 | + while (currRow < numRows && currCol >= 0) { |
| 18 | + if (binaryMatrix.get(currRow, currCol) == 0) { |
| 19 | + currRow++; |
| 20 | + } else { |
| 21 | + currCol--; |
20 | 22 | }
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21 | 23 | }
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22 |
| - return minIdx == Integer.MAX_VALUE ? -1 : minIdx; |
23 |
| - } |
24 |
| - |
25 |
| - private int binarySearch(BinaryMatrix binaryMatrix, int row, int start, int end) { |
26 |
| - int minIdx = Integer.MAX_VALUE; |
27 |
| - while (start <= end) { |
28 |
| - int mid = (start + end) / 2; |
29 |
| - if (binaryMatrix.get(row, mid) == 1) { |
30 |
| - minIdx = Math.min(minIdx, mid); |
31 |
| - end = mid - 1; |
32 |
| - } |
33 |
| - else { |
34 |
| - start = mid + 1; |
35 |
| - } |
36 |
| - } |
37 |
| - return minIdx == Integer.MAX_VALUE ? -1 : minIdx; |
| 24 | + return currCol == numCols - 1 ? -1 : currCol + 1; |
38 | 25 | }
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39 | 26 | }
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