low
to 0 and high
to the length of the string s
.perm
of size n + 1
to hold the permutation.s
using an index i
:
s[i]
is 'I', set perm[i]
to low
and increment low
.s[i]
is 'D', set perm[i]
to high
and decrement high
.perm[n]
to the remaining value of low
(which is equal to high
at this point).perm
.