diff options
Diffstat (limited to '2020')
| -rw-r--r-- | 2020/day08.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/2020/day08.c b/2020/day08.c index 87b4585..7afd969 100644 --- a/2020/day08.c +++ b/2020/day08.c @@ -5,6 +5,7 @@ static struct Ins { char op[4]; int arg; } prog[1024]; +static int len; static int acc; static int pc; static void step(void) { @@ -16,14 +17,31 @@ static void step(void) { } pc++; } -int main(void) { - int i = 0; - while (EOF != scanf("%s %d\n", prog[i].op, &prog[i].arg)) { - i++; - } +static int terminates(void) { + acc = 0; + pc = 0; int ran[1024] = {0}; - while (!ran[pc]++) { + while (!ran[pc]++ && pc < len) { step(); } + return pc == len; +} +int main(void) { + while (EOF != scanf("%s %d\n", prog[len].op, &prog[len].arg)) { + len++; + } + terminates(); + printf("%d\n", acc); + for (int i = 0; i < len; ++i) { + if (!strcmp(prog[i].op, "jmp")) { + strcpy(prog[i].op, "nop"); + if (terminates()) break; + strcpy(prog[i].op, "jmp"); + } else if (!strcmp(prog[i].op, "nop")) { + strcpy(prog[i].op, "jmp"); + if (terminates()) break; + strcpy(prog[i].op, "nop"); + } + } printf("%d\n", acc); } |