I got horribly confused with this one so thought I would shed some light on the practice questions:

abba

a|0,0| a|3,3|

b|1,1| b|2,2|

ab|0,1| ab|2,3|

abb|0,2| abb|1,3|

4

abcd

0

ifailuhkqq

i|0,0| i|3,3|

q|8,8| q|9,9|

afi|0,2| afi|1,3|

3

hucpoltgty

t|6,6| t|8,8|

gt|6,7| gt|7,8|

2

ovarjsnrbf

r|3,3| r|7,7|

jnrs|3,6| jnrs|4,7|

2

pvmupwjjjf

p|0,0| p|4,4|

j|6,6| j|7,7|

j|6,6| j|8,8|

j|7,7| j|8,8|

jj|6,7| jj|7,8|

mpuv|0,3| mpuv|1,4|

6

iwwhrlkpek

w|1,1| w|2,2|

k|6,6| k|9,9|

ekp|6,8| ekp|7,9|

3

Zero indexed showing initial string, numbers and each match.