advent2023

commit 51a244f055d4f0177ba944588faeb746acf8c0f9
parent 54fd25077b19ed9ce6d4c5a42b54bf8ce0bc0ff7
Author: bsandro <email@bsandro.tech>
Date:   Wed,  6 Dec 2023 22:19:57 +0200

day 06 p1+p2 so lazy I didn't even bother to parse the data

Diffstat:
A
day06/Makefile
 | 
25
+++++++++++++++++++++++++
A
day06/input.txt
 | 
2
++
A
day06/main.c
 | 
30
++++++++++++++++++++++++++++++
A
day06/puzzle.c
 | 
86
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
day06/test.txt
 | 
2
++

5 files changed, 145 insertions(+), 0 deletions(-)
diff --git a/day06/Makefile b/day06/Makefile
@@ -0,0 +1,25 @@
+NAME=$(shell basename ${PWD})
+SRC=$(wildcard *.c)
+DEPS:=$(wildcard *.h)
+OBJ:=$(SRC:.c=.o)
+CFLAGS=-O2 -std=c11 -Werror -Wall -Wextra -I. -I../common
+LDFLAGS=-lc
+
+all: $(NAME)
+
+.PHONY: clean run
+
+clean:
+	rm -f $(OBJ) $(NAME)
+
+%.o : %.c $(DEPS)
+	@$(CC) $(CFLAGS) -c $< -o $@
+
+$(NAME): $(OBJ)
+	@$(CC) $(OBJ) -o $@ $(LDFLAGS)
+
+run: $(NAME)
+	@./$(NAME) input.txt
+
+test: $(NAME)
+	@./$(NAME) test.txt
diff --git a/day06/input.txt b/day06/input.txt
@@ -0,0 +1,2 @@
+Time:        45     97     72     95
+Distance:   305   1062   1110   1695
diff --git a/day06/main.c b/day06/main.c
@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <time.h>
+#include <string.h>
+
+void puzzle(const char *filename, long long *res1, long long *res2);
+//void puzzle_test(const char *filename, long long *res1, long long *res2);
+
+int main(int argc, char *argv[]) {
+	printf("Advent of Code: day 06\n");
+	double time_start = clock();
+
+	if (argc <= 1) {
+		printf("Usage: %s inputfile.txt\n", argv[0]);
+		return -1;
+	}
+
+	const char *filename = argv[1];
+	long long counter1 = -1;
+	long long counter2 = -1;
+
+	puzzle(filename, &counter1, &counter2);
+
+	printf("Puzzle #1: %lld\n", counter1);
+	printf("Puzzle #2: %lld\n", counter2);
+
+	double elapsed = clock() - time_start;
+	printf("Elapsed: %f\n", elapsed / CLOCKS_PER_SEC);
+
+	return 0;
+}
diff --git a/day06/puzzle.c b/day06/puzzle.c
@@ -0,0 +1,86 @@
+#define _DEFAULT_SOURCE
+
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <strings.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#define STR_LEN 2048
+
+bool is_digit(char b) {
+	return b>='0' && b<='9';
+}
+
+// I'll skip the parse part for now
+
+typedef struct Race {
+	int time;
+	int record;
+} Race;
+
+void puzzle(const char *filename, long long *result1, long long *result2) {
+	FILE *infile = fopen(filename, "r");
+	if (infile == NULL) {
+		fprintf(stderr, "fopen() error: %s\n", strerror(errno));
+		return;
+	}
+
+	char buf[STR_LEN] = {0};
+	unsigned int line_num = 0;
+
+	*result1 = 0;
+	*result2 = 0;
+
+	while (fgets(buf, STR_LEN, infile) != NULL) {
+
+		++line_num;
+		bzero(buf, STR_LEN);
+	}
+
+	// test data
+	/*Race races[3] = {
+		{ .time = 7, .record = 9 },
+		{ .time = 15, .record = 40 },
+		{ .time = 30, .record = 200 }
+	};*/
+
+	// real data
+	Race races[4] = {
+		{ .time = 45, .record = 305 },
+		{ .time = 97, .record = 1062 },
+		{ .time = 72, .record = 1110 },
+		{ .time = 95, .record = 1695 },
+	};
+
+	*result1 = 1;
+	for (int i=0; i<4; ++i) {
+		int wins = 0;
+		for (int t=1; t<races[i].time; ++t) { // holding the button
+			int speed = t;
+			int time = races[i].time-t;
+			int dist = speed*time;
+			if (dist>races[i].record) wins++;
+		}
+		//printf("wins: %d\n", wins);
+		*result1 *= wins;
+	}
+
+	{
+		int wins = 0;
+		for (uint64_t t=1; t<45977295; ++t) { // holding the button
+			uint64_t speed = t;
+			uint64_t time = 45977295-t;
+			uint64_t dist = speed*time;
+			if (dist>305106211101695) wins++;
+		}
+		*result2 = wins;
+	}
+
+	// mutiny! ignoring feof/ferror.
+	fclose(infile);
+}
diff --git a/day06/test.txt b/day06/test.txt
@@ -0,0 +1,2 @@
+Time:      7  15   30
+Distance:  9  40  200