advent2021

commit 43bfbc12e61030402e89be352b802f9f478f20f0
parent a759041c799d1e2d968b863ca7291a26e7e469b5
Author: bsandro <brian.drosan@gmail.com>
Date:   Sat, 25 Dec 2021 01:44:44 +0200

Day 24, part 1+2 solution made by hand but the puzzle was not fun anyway

Diffstat:
M
day24/puzzle.c
 | 
39
+++++++++++++++++++++++----------------

1 file changed, 23 insertions(+), 16 deletions(-)
diff --git a/day24/puzzle.c b/day24/puzzle.c
@@ -41,6 +41,7 @@ int exec_eql(struct cmd_t *cmd, int (*registers)[5]);
 int read_input(struct input_t *input);
 struct input_t make_input(uint64_t number);
 bool valid_input(struct input_t *input);
+bool validate_number(struct array_t *commands, uint64_t num);
 
 void puzzle(const char *filename, long long *result1, long long *result2) {
 	FILE *infile = fopen(filename, "r");
@@ -58,28 +59,34 @@ void puzzle(const char *filename, long long *result1, long long *result2) {
 		bzero(buf, STR_LEN);
 	}
 
-	for (uint64_t i = 99999999999999; i >= 11111111111111; --i) {
-		struct input_t input = make_input(i);
-		if (valid_input(&input)) {
-			int registers[5] = {0};
-			for (size_t k = 0; k < commands.count; ++k) {
-				struct cmd_t *cmd = &((struct cmd_t *)commands.data)[k];
-				exec_cmd(cmd, &registers, &input);
-			}
-			input.current = 0;
-			if (registers[4] == 0) {
-				*result1 = i;
-				break;
-			}
-		}
+	uint64_t max_num = 94992992796199;
+	uint64_t min_num = 11931881141161;
+
+	if (validate_number(&commands, max_num)) {
+		*result1 = max_num;
 	}
 
-	*result2 = 0;
+	if (validate_number(&commands, min_num)) {
+		*result2 = min_num;
+	}
 
 	// mutiny! ignoring feof/ferror.
 	fclose(infile);
 }
 
+bool validate_number(struct array_t *commands, uint64_t num) {
+	struct input_t input = make_input(num);
+	if (valid_input(&input)) {
+		int registers[5] = {0};
+		for (size_t k = 0; k < commands->count; ++k) {
+			struct cmd_t *cmd = &((struct cmd_t *)commands->data)[k];
+			exec_cmd(cmd, &registers, &input);
+		}
+		return registers[4] == 0;
+	}
+	return false;
+}
+
 void parse_command(struct array_t *commands, char *str) {
 	assert(commands != NULL);
 	assert(str != NULL);
@@ -204,6 +211,6 @@ int exec_mod(struct cmd_t *cmd, int (*registers)[5]) {
 int exec_eql(struct cmd_t *cmd, int (*registers)[5]) {
 	assert(cmd != NULL);
 	int r = cmd->reg2 > 0 ? (*registers)[cmd->reg2] : cmd->op2;
-	(*registers)[cmd->reg1] = (*registers)[cmd->reg1] == r ? 1 : 0;
+	(*registers)[cmd->reg1] = ((*registers)[cmd->reg1] == r) ? 1 : 0;
 	return (*registers)[cmd->reg1];
 }