O(n)func countkmers(sequence string, k int) map[string]int {O(1) var kmers = make(map[string]int)---- O(1) if k > len(sequence) || k <= 0 {O(1) return kmers---- }---- O(1) var tempSequence = sequence[:k]O(1) kmers[tempSequence]++---- O(n) for i := k; i < len(sequence); i++ {O(1) tempSequence = tempSequence[1:] + sequence[i:i+1]O(1) kmers[tempSequence]++---- }---- O(1) return kmers----}