二分查找-寻找第一个比target小的值

双闭区间写法，需要取high

    private int max_bound(int[][] matrix, int column, int target) {
        int m = matrix.length;
        int l = 0;
        int h = m - 1;
        while (l <= h) {
            int mid = l + ((h - l) >> 1);
            if (matrix[mid][column] > target) {
                h = mid - 1;
            } else {
                l = mid + 1;
            }
        }
        return h;
    }