利用横向递归算法解决数据组合的问题， 比如数组为a, 长度为len， 横向递归 B display(a,len) b是二维数组，a是一维数组-the use of horizontal recursive algorithm to solve the problem of data sets, such as the array is a length of len, horizontal display recursive B (a, len) b is the two-dimensional array, is a one-dimensional arrays