2023 day1

2023/day1/solution.c

@@ -1,11 +1,90 @@
 #include <stdint.h>
 
+#include "parse.h"
+
+typedef int (* digit_parser_t)(const char * start, const char * end);
+
+static int part1_digit_parser(const char * start, const char * end)
+{
+  return parse_base10_digit(*start);
+}
+
+static int part2_digit_parser(const char * start, const char * end)
+{
+  int length = end - start;
+  if (length >= 1) {
+    int n = parse_base10_digit(*start);
+    if (n >= 0) return n;
+  }
+  if (length >= 3) {
+    if (parse_match(start, "one")) return 1;
+    if (parse_match(start, "two")) return 2;
+    if (parse_match(start, "six")) return 6;
+  }
+  if (length >= 4) {
+    if (parse_match(start, "four")) return 4;
+    if (parse_match(start, "five")) return 5;
+    if (parse_match(start, "nine")) return 9;
+  }
+  if (length >= 5) {
+    if (parse_match(start, "three")) return 3;
+    if (parse_match(start, "seven")) return 7;
+    if (parse_match(start, "eight")) return 8;
+  }
+  return -1;
+}
+
+static int parse_digit_left(const char * start, const char * end, digit_parser_t parser)
+{
+  while (start < end) {
+    int digit = parser(start, end);
+    if (digit >= 0) {
+      return digit;
+    }
+    start++;
+  }
+  return -1;
+}
+
+static int parse_digit_right(const char * start, const char * end, digit_parser_t parser)
+{
+  const char * s = end - 1;
+  while (s >= start) {
+    int digit = parser(s, end);
+    if (digit >= 0) {
+      return digit;
+    }
+    s--;
+  }
+  return -1;
+}
+
+int solve(const char * input, int length, digit_parser_t parser)
+{
+  const char * end = input + length;
+
+  int sum = 0;
+
+  while (input < end) {
+    const char * newline = parse_find(input, '\n');
+    int left = parse_digit_left(input, newline, parser);
+    int right = parse_digit_right(input, newline, parser);
+
+    sum += left * 10 + right;
+
+    input = newline + 1;
+  }
+
+
+  return sum;
+}
+
 int64_t _2023_day1_part1(const char * input, int length)
 {
-  return -1;
+  return solve(input, length, part1_digit_parser);
 }
 
 int64_t _2023_day1_part2(const char * input, int length)
 {
-  return -1;
+  return solve(input, length, part2_digit_parser);
 }

Makefile

@@ -13,6 +13,7 @@ CFLAGS += -Wno-char-subscripts
 LIB ?= $(MAKEFILE_PATH)/dreamcast
 
 libgcc/%.o: $(LIBGCC)
+	@mkdir -p $(dir $@)
 	ar x --output $(dir $@) $(LIBGCC) $(notdir $@)
 	sh4-none-elf-objdump -t $@ \
 		| grep -E '[.]hidden' \

input_dreamcast.c

@@ -25,7 +25,7 @@ void open_input(int ix, char ** buf, int * length)
 
 void open_sample(int ix, int part, char ** buf, int * length)
 {
-  if (ix < 1 || ix > input_size || part < 0 || part > 1) {
+  if (ix < 0 || ix > input_size || part < 0 || part > 1) {
     *buf = NULL;
     *length = 0;
   } else {

parse.c

@@ -3,25 +3,6 @@
 
 #include "parse.h"
 
-const char * parse_skip(const char * s, char c)
-{
-  while (*s == c) {
-    s++;
-  }
-  return s;
-}
-
-const char * parse_find_first_right(const char * s, int length, char c)
-{
-  const char * ss = &s[length - 1];
-  while (ss >= s) {
-    if (*ss == c)
-      return ss;
-    ss--;
-  }
-  return s;
-}
-
 int parse_base10_digit(char c)
 {
   switch (c) {
@@ -39,6 +20,33 @@ int parse_base10_digit(char c)
   }
 }
 
+const char * parse_skip(const char * s, char c)
+{
+  while (*s == c) {
+    s++;
+  }
+  return s;
+}
+
+const char * parse_find(const char * s, char c)
+{
+  while (*s != c) {
+    s++;
+  }
+  return s;
+}
+
+const char * parse_find_first_right(const char * s, int length, char c)
+{
+  const char * ss = &s[length - 1];
+  while (ss >= s) {
+    if (*ss == c)
+      return ss;
+    ss--;
+  }
+  return s;
+}
+
 const char * parse_base10(const char * s, int * n)
 {
   *n = 0;

parse.h

@@ -7,6 +7,7 @@ extern "C" {
 #endif
 
 const char * parse_skip(const char * s, char c);
+const char * parse_find(const char * s, char c);
 const char * parse_find_first_right(const char * s, int length, char c);
 int parse_base10_digit(char c);
 const char * parse_base10(const char * s, int * n);

runner.c

@@ -26,6 +26,7 @@ bool runner_tick(struct runner_state * runner_state)
 {
   int tick = (solution_ticks - 1) - runner_state->tick;
   //int tick = runner_state->tick;
+  runner_state->tick += 1;
 
   if (tick < 0) {
     runner_state->want_render = false;
@@ -37,18 +38,20 @@ bool runner_tick(struct runner_state * runner_state)
   int year = solution[ix].year;
   int day = solution[ix].day;
 
+  if (year != 2023) {
+    return false;
+  }
+
   runner_state->want_render = solution[ix].render != NULL;
 
   char * buf;
   int length;
-  open_sample(ix, part, &buf, &length);
+  //open_sample(ix, part, &buf, &length);
-  //open_input(ix, &buf, &length);
+  open_input(ix, &buf, &length);
-  int64_t answer = solution[day].part[part](buf, length);
+  int64_t answer = solution[ix].part[part](buf, length);
 
   printf("%d day %d part %d: %l\n", year, day, part + 1, answer);
 
-  runner_state->tick += 1;
-
   return false;
 }