a substre string contiguous subsequence string so stre bca substre string abcabc string cc nota repeat block string form concatenate string so stre abcabc repeat block string abcabd ababab notYouve get sequence latin character stre at step find short substring repeat block exist choose leftmost as substre form XX x string replace substre x word delete x substring substre you repeat process remains repeat block string how final string look like Look sample explanation understand statement precise