Find lexicographically largest subsequence of s [ 0. . n - 1 ] such that every character appears at least k times . The result is filled in t [ ]
def subsequence ( s , t , n , k ) : NEW_LINE INDENT last = 0 NEW_LINE cnt = 0 NEW_LINE new_last = 0 NEW_LINE size = 0 NEW_LINE string = ' zyxwvutsrqponmlkjihgfedcba ' NEW_LINE DEDENT