Created
February 27, 2021 12:36
-
-
Save harieamjari/2ee9c7b119642ced6ddb6374a81908d9 to your computer and use it in GitHub Desktop.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* REPLY CHALLENGE | |
* | |
* Minimal deterministic parser | |
*/ | |
#include <stdio.h> | |
#include <stdlib.h> | |
#define ERROR(...) fprintf(stderr, __VA_ARGS__) | |
#define UNEXPECTED(x) {\ | |
if (x!=TOK_ERR) \ | |
ERROR("[%s @ %d] %s:%d:%d error: unexpected %s\n", __FILE__, __LINE__,\ | |
fname, line_token_found, column_token_found, tok_to_str(x)); \ | |
fclose(fp);\ | |
return 1; \ | |
} | |
#define EXPECTING(x) {\ | |
if (x!=TOK_ERR) \ | |
ERROR("[%s @ %d] %s:%d:%d error: expecting %s\n", __FILE__, __LINE__,\ | |
fname, line_token_found, column_token_found, tok_to_str(x)); \ | |
fclose(fp);\ | |
return 1; \ | |
} | |
typedef enum token_t token_t; | |
enum token_t | |
{ | |
TOK_NUM, | |
TOK_NEWLINE, | |
TOK_EOF, | |
TOK_ERR | |
}; | |
int line_token_found; | |
int column_token_found; | |
int tok_num; | |
FILE *fp; | |
char *fname; | |
char * | |
tok_to_str (token_t t) | |
{ | |
switch (t) | |
{ | |
case TOK_NEWLINE: | |
return "newline"; | |
case TOK_NUM: | |
return "numeric"; | |
case TOK_EOF: | |
return "end of file"; | |
default: | |
return "internal err!"; | |
} | |
} | |
/*-------. | |
|scanner| | |
`------*/ | |
token_t | |
lex (void) | |
{ | |
static int line = 1; | |
static int column = 1; | |
int c; | |
char buff[100] = { 0 }; | |
/* eat whitespace */ | |
while ((c = fgetc (fp)) == (int) ' ') | |
column++; | |
if (c == (int) '\n') | |
{ | |
column = 1; | |
line++; | |
return TOK_NEWLINE; | |
} | |
line_token_found = line; | |
column_token_found = column; | |
switch (c) | |
{ | |
case '-': | |
case '0': | |
case '1': | |
case '2': | |
case '3': | |
case '4': | |
case '5': | |
case '6': | |
case '7': | |
case '8': | |
case '9': | |
{ | |
ungetc (c, fp); | |
int _column; | |
fscanf (fp, "%d%n", &tok_num, &_column); | |
column += _column; | |
return TOK_NUM; | |
} | |
case EOF: | |
return TOK_EOF; | |
default: | |
ERROR ("%s:%d:%d \x1b[1;31merror\x1b[0m:" | |
" illegal character '%c'\n", fname, line_token_found, | |
column_token_found, c); | |
return TOK_ERR; | |
} | |
} | |
int | |
main (int argc, char **argv) | |
{ | |
if (argc != 2) | |
{ | |
ERROR ("syntax: %s [infile]\n", argv[0]); | |
return 1; | |
} | |
fname = argv[1]; | |
fp = fopen (argv[1], "r"); | |
if (fp == NULL) | |
{ | |
perror (argv[1]); | |
return 1; | |
} | |
token_t tok; | |
int state_case; | |
int friends; | |
int k; | |
int flag = 1; | |
/* start parsing */ | |
while ((tok = lex ()) == TOK_NEWLINE); | |
if (tok != TOK_NUM) | |
UNEXPECTED (tok); | |
state_case = tok_num; | |
for (int ccase = 0; ccase < state_case; ccase++) | |
{ | |
while ((tok = lex ()) == TOK_NEWLINE); | |
if (tok != TOK_NUM) | |
EXPECTING (TOK_NUM); | |
friends = tok_num; | |
while ((tok = lex ()) == TOK_NEWLINE); | |
int buff[1000]; | |
memset (buff, 0, 1000); | |
for (int i = 0; i < friends; i++) | |
{ | |
if (tok != TOK_NUM) | |
EXPECTING (TOK_NUM); | |
buff[i] = tok_num; | |
tok = lex (); | |
} | |
int num = 0; | |
int k = 0; | |
int flag; | |
while (1) | |
{ | |
flag = 0; | |
num = 0; | |
for (int i = 0; i < friends; i++) | |
{ | |
if (!buff[i]) | |
{ | |
if (num) | |
{ | |
num = 0; | |
break; | |
} | |
continue; | |
} | |
flag = 1; | |
buff[i]--; | |
num = 1; | |
} | |
k++; | |
if (!flag) | |
break; | |
} | |
if (tok != TOK_NEWLINE) | |
EXPECTING (TOK_NEWLINE); | |
printf ("Case #%d: %d\n", ccase + 1, k - 1); | |
} | |
while ((tok = lex ()) == TOK_NEWLINE); | |
if (tok != TOK_EOF) | |
UNEXPECTED (tok); | |
fclose (fp); | |
return 0; | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment