It's subseqence. For instance, in ABXCDYEFGZ QARBCSTDEFG You want to find [Q]A[R]B(X)C[ST]D(Y)EFG(Z) ABCDEFG is the longest common subsequence, QRST are the

It's subseqence. For instance, in ABXCDYEFGZ QARBCSTDEFG You want to find [Q]A[R]B(X)C[ST]D(Y)EFG(Z) ABCDEFG is the longest common subsequence, QRST are the additions and XYZ are the deletions.