private int searchColumns(char[][] image, int i, int j, int top, int bottom, boolean opt) {
        int result = 0;
        while (i <= j) {
            int k = top;
            int mid = (i + j)/2;
            while (k <= bottom && image[k][mid] == '0') {
                k++;
            }
            if (k != bottom + 1) {
                result = mid;
            }
            if ((k == bottom + 1) == opt) {
                i = mid + 1;
            } else {
                j = mid - 1;
            }
        }
        return result;
    }
An image is represented by a binary matrix with 0 as a white pixel and 1 as a black pixel.
The black pixels are connected, i.e., there is only one black region. Pixels are connected horizontally
and vertically. Given the location (x, y) of one of the black pixels, return the area of the smallest
(axis-aligned) rectangle that encloses all black pixels.
https://leetcode.com/problems/smallest-rectangle-enclosing-black-pixels/
src/com/interview/multiarray/SmallestRectangleBlackPixel.java