Search a 2D Array

public boolean searchMatrix(int[][] matrix, int target) {

    if (matrix.length == 0) {
        return false;
    }

    int start = 0;
    int rows = matrix.length;
    int cols = matrix[0].length;
    int end = rows * cols - 1;
    int mid;

    while (start + 1 < end) {
        mid = start + (end - start) / 2;
        int midValue = matrix[mid / cols][mid % cols];
        if (midValue == target) {
            return true;
        } else if (midValue > target) {
            end = mid;
        } else if (midValue < target) {
            start = mid;
        }
    }

    int startValue = matrix[start / cols][start % cols];
    int endValue = matrix[end / cols][end % cols];

    if (startValue == target || endValue == target) {
        return true;
    } else {
        return false;
    }
}