Suppose a given string sequence "AGCGTNCGTNGTACGTNACGTNAACGTN"

the string consists of only one line and all uppercase alphabets A,G,T,C,N

Here A,G,T,C are considered valid characters and N is like a break point.

I have to make k-mer sequences. (k >= 2 && k <=10).

suppose the sequence "ACGNACGCTN"

suppose k = 3

I have to output the unique kmer formed in the sequence and the number of times it appears in the sequence.

like

ACG 2

CGC 1

GCT 1

If you encounter an N in the sequence, you simply check for the kmer from position (N+1) and so on.

I have to implement this using arrays or vectors.

The string sequence file can be over 100mb in size so please keep in check with algorithm runtimes (like dont use any nested for loops)

No hashmaps or any use of dictionaries like maps.