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{\narrower\smallskip\noindent
{\bf Exercise.} (Strings)

\noindent
Given a word {\tt C} from a cryptogram and a word {\tt D} from the dictionary,
determine if there is a cryptographic substitution that changes~{\tt C}
into~{\tt D}. The rules of cryptographic substitution are that no letter
can be substituted for itself, and no letter can be substituted for
more than one letter. Examples:
$$\vcenter{\halign{\ctr{\tt #}\qquad&\ctr{\tt #}\qquad&\ctr{#}\cr
C&D&Answer\cr
\noalign{\smallskip}
ABBAC&TEETH&YES\cr
ABBAC&TRUTH&NO\cr
ABBAC&ARRAY&NO\cr
RQQJY&TEETH&NO\cr}}$$

\smallskip}

{\narrower\smallskip\noindent
{\bf Exercise.} (Strings)

\noindent
Write a program to pretend to be a therapist, reading sentences in English from
the terminal. If an input sentence contains ``am'', the program should respond by
a confirmation, changing ``am'' to ``are'', ``I''~to ``you'', etc.:

\line{\qquad\qquad\qquad Input: I am angry.\hfil}
\line{\qquad\qquad\qquad Output: You say you are angry.\hfil}

It should respond to sentences containing family names, like ``brother'', with
``Tell me more about your family.''

It should respond to ``I don't like (trust, etc.) you'' with ``I'm only trying to
help you.'' If all else fails, it should say ``Yes,'' or ``Go on,'' or the like.
\smallskip}


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\copyright 1984 Robert W. Floyd

First draft March 28, 1984 

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