Time Limit: 1000 ms Memory Limit: 65536 KiB
TEX is a typesetting language developed by Donald Knuth. It takes
source text together with a few typesetting instructions and produces,
one hopes, a beautiful document. Beautiful documents use
double-left-quote and double-right-quote to delimit quotations, rather
than the mundane " which is what is provided by most keyboards.
Keyboards typically do not have an oriented double-quote, but they do
have a left-single-quote ` and a right-single-quote '. Check your
keyboard now to locate the left-single-quote key ` (sometimes called
the "backquote key") and the right-single-quote key ' (sometimes
called the "apostrophe" or just "quote"). Be careful not to confuse
the left-single-quote ` with the "backslash" key \. TEX lets the user
type two left-single-quotes `` to create a left-double-quote and two
right-single-quotes '' to create a right-double-quote. Most typists,
however, are accustomed to delimiting their quotations with the
un-oriented double-quote ".
If the source contained
"To be or not to be," quoth the bard, "that is the question."
then the typeset document produced by TEX would not contain the
desired form: "To be or not to be," quoth the bard, "that is the
question." In order to produce the desired form, the source file must
contain the sequence:
``To be or not to be,'' quoth the bard, ``that is the question.''
You are to write a program which converts text containing double-quote
(") characters into text that is identical except that double-quotes
have been replaced by the two-character sequences required by TEX for
delimiting quotations with oriented double-quotes. The double-quote
(") characters should be replaced appropriately by either `` if the "
opens a quotation and by '' if the " closes a quotation. Notice that
the question of nested quotations does not arise: The first " must be
replaced by ``, the next by '', the next by ``, the next by '', the
next by ``, the next by '', and so on.
Input will consist of several lines of text containing an even number
of double-quote (") characters. Input is ended with an end-of-file
character. The text must be output exactly as it was input except
* the first " in each pair is replaced by two ` characters: `` and
* the second " in each pair is replaced by two ' characters: ''.
"To be or not to be," quoth the Bard, "that is the question". The programming contestant replied: "I must disagree. To `C' or not to `C', that is The Question!"
``To be or not to be,'' quoth the Bard, ``that is the question''. The programming contestant replied: ``I must disagree. To `C' or not to `C', that is The Question!''