LCS:

S,T S A T B 4LCS(A,B)AB

LCS(A,B) A,B

S A S (0)(0)(BABABABABBAABABA)

S A S (0)(BBAABABABBAAABABA)

:

n,m(1<=n,m<=5000)

S

T

:

:

4 5 abba babab

:

5