Number of sliding window in the string

Question

I have to calculate number of sliding window in a string.

If the sample string is "CHECKIT" and window size is 2 then

1. CH
2. HE
3. EC
4. CK
5. KI
6. IT

Window size may vary for the string.

Answer 1

For a word with $n$ alphabets, for eg. ALPHABETS has 9 alphabets. Of this, window size is $k$. Total possible ways will be:

$$P = n - k + 1 = 9 - k + 1 = 10 - k$$

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$ k = 2 $

1. AL
2. LP
3. PH
4. HA
5. AB
6. BE
7. ET
8. TS

$k = 4$

1. ALPH
2. LPHA
3. PHAB
4. HABE
5. ABET
6. BETS

and so on...