c++ - Mapping a string to a unique number? -

is there nice bash 1 liner map strings inside file unique number?

for instance,

a b b c c 

should converted into

1 1 2 2 3 3 

i implementing in c++ bash one-liner great.

awk '{if (!($0 in ids)) ids[$0] = ++i; print ids[$0]}' 

this maintains associative array called ids. each time finds new string assigns monotically increasing id ++i.

example:

jkugelman$ echo $'a\nb\nc\na\nb\nc' | awk '{if (!($0 in ids)) ids[$0] = ++i; print ids[$0]}' 1 2 3 1 2 3