Given two sequences A
and B
, find out number of unique ways to transform sequence A
into sequence B
. Transformation means converting string A
(by removing 0 or more characters) to string B.
When inputs are A = "abcccdf"
and B = "abccdf"
, the output should be 3
. Three ways to transform A
into B
are "ab.ccdf"
, "abc.cdf"
and "abcc.df"
.
When inputs are A = "aabba"
and B = "ab"
, the output should be 4
. Four ways to transform A
into B
are "a.b.."
, "a..b."
, ".ab.."
and ".a.b."
.