visible in an unambiguous way. РCategory 0 РGregory Pietsch pointed out that my solution was actually Category 1. He was quite right. Better still, he was kind enough to submit a Category 0 solution himself. Here it is: Р/* Gregory Pietsch <gkp1@> */Р/*Р * Here's my attempt at a Category 0 version of 1-10.Р *Р * Gregory PietschР */Р#include <stdio.h>Рint main()Р{Р int c, d;Р while ( (c=getchar()) != EOF) {Р d = 0;Р if (c == '\\') {Р putchar('\\');Р putchar('\\');Р d = 1;Р }Р if (c == '\t') {Р putchar('\\');Р putchar('t');Р d = 1;Р }Р if (c == '\b') {Р putchar('\\');Р putchar('b');Р d = 1;Р }Р if (d == 0)Р putchar(c); Р }Р return 0;Р}РCategory 1 РThis solution, which I wrote myself, is the sadly discredited Cat 0 answer which has found a new lease of life in Category 1. Р#include <stdio.h>