I have implemented the longest common subsequence problem as instructed in this video. It just execute first set of code and produces an empty list. What is wrong with this implementation?
def lcs_recursive(xlist,ylist):
if not xlist or ylist:
return []
x,xs,y,ys, = xlist[0],xlist[1:],ylist[0],ylist[1:]
if x == y:
return [x] + lcs_recursive(xs,ys)
else:
return max(lcs_recursive(xlist,ys),lcs_recursive(xs,ylist),key=len)
s1 = 'abc'
s2 = 'aeb'
print lcs_recursive(s1,s2)