|
| 1 | +class Solution { |
| 2 | + public int largest1BorderedSquare(int[][] grid) { |
| 3 | + int m = grid.length, n = grid[0].length; |
| 4 | + int[][] down = new int[m][n]; |
| 5 | + int[][] right = new int[m][n]; |
| 6 | + for (int i = m - 1; i >= 0; --i) { |
| 7 | + for (int j = n - 1; j >= 0; --j) { |
| 8 | + if (grid[i][j] == 1) { |
| 9 | + down[i][j] += i + 1 < m ? down[i + 1][j] + 1 : 1; |
| 10 | + right[i][j] += j + 1 < n ? right[i][j + 1] + 1 : 1; |
| 11 | + } |
| 12 | + } |
| 13 | + } |
| 14 | + for (int len = Math.min(m, n); len > 0; --len) { |
| 15 | + for (int i = 0; i <= m - len; ++i) { |
| 16 | + for (int j = 0; j <= n - len; ++j) { |
| 17 | + if (down[i][j] >= len && right[i][j] >= len && right[i + len - 1][j] >= len && down[i][j + len - 1] >= len) { |
| 18 | + return len * len; |
| 19 | + } |
| 20 | + } |
| 21 | + } |
| 22 | + } |
| 23 | + return 0; |
| 24 | + } |
| 25 | +} |
0 commit comments