From 5afa103769518b795d4b391f5e14d5be048a142f Mon Sep 17 00:00:00 2001
From: "Alexander \"Arav\" Andreev" <me@arav.su>
Date: Wed, 6 Dec 2023 03:15:44 +0400
Subject: [PATCH] Day 5 part 2 complete! Heh, it takes around 91.217s +- 6s to
 run. :) So a test for day5 with my data is commented out. :)

---
 Makefile  |   2 +-
 day5/p2.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 test      |   5 ++-
 3 files changed, 132 insertions(+), 2 deletions(-)
 create mode 100644 day5/p2.c

diff --git a/Makefile b/Makefile
index 6e32d46..2da10eb 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ day4: day4/p1.c day4/p2.c
 
 day5: day5/p1.c day5/p2.c
 	${CC} ${CFLAGS} $@/p1.c -o bin/$@p1
-# ${CC} ${CFLAGS} $@/p2.c -o bin/$@p2
+	${CC} ${CFLAGS} -fopenmp $@/p2.c -o bin/$@p2
 
 clean:
 	rm -f bin/day*p*
\ No newline at end of file
diff --git a/day5/p2.c b/day5/p2.c
new file mode 100644
index 0000000..c14fa2a
--- /dev/null
+++ b/day5/p2.c
@@ -0,0 +1,127 @@
+#define  _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+
+#define ABS(n) ((n < 0) ? n * -1 : n)
+
+
+uint64_t parse_number(char *end);
+
+#define MAPS_LEN 7
+
+typedef struct {
+    uint64_t dst, src, rng;
+} map_t;
+
+
+int main(int argc, char **argv) {
+    FILE *input;
+    char *line = NULL;
+    size_t line_buf_length = 0;
+
+    if (argc == 1 || argv[1][0] == '-')
+		input = stdin;
+	else if ((input = fopen(argv[1], "r")) == NULL) {
+		printf("Cannot open file %s\n", argv[1]);
+		return -1;
+	}
+
+    uint64_t *seed_ranges = NULL;
+
+    getline(&line, &line_buf_length, input);
+
+    char *colon_pos = strchr(line, ':');
+
+    size_t seed_ranges_len = 0;
+    for (char *space_pos = colon_pos+1; space_pos != NULL; space_pos = strchr(space_pos, ' ')) {
+        seed_ranges_len++;
+        space_pos++;
+    }
+
+    seed_ranges = (uint64_t *) calloc(seed_ranges_len, sizeof(uint64_t));
+
+    for (size_t i = 0, seeds_pos = (size_t) colon_pos+2;; seeds_pos++) {
+        while (*(char *)(seeds_pos)>>4 == 0x3) seeds_pos++;
+        seed_ranges[i++] = parse_number((char *)(seeds_pos-1));
+        if (*(char *)seeds_pos == '\n')
+            break;
+    }
+
+    map_t **maps = (map_t **) calloc(MAPS_LEN, sizeof(map_t *));
+    for (size_t i = 0; i < MAPS_LEN; ++i)
+        maps[i] = (map_t *) calloc(1, sizeof(map_t));
+    size_t map_lengths[MAPS_LEN] = {1};
+
+    int8_t maps_cur = -1;
+    while (getline(&line, &line_buf_length, input) != -1) {
+        if (maps_cur == MAPS_LEN)
+            break;
+        if (line[0] == '\n') {
+            maps_cur++;
+            continue;
+        } else if (line[0]>>4 != 0x3) {
+            continue;
+        }
+
+        map_lengths[maps_cur]++;
+        maps[maps_cur] = (map_t *) realloc(maps[maps_cur], map_lengths[maps_cur] * sizeof(map_t));
+
+        map_t new_range_map = {0};
+        sscanf(line, "%lu %lu %lu\n", &new_range_map.dst, &new_range_map.src, &new_range_map.rng);
+
+        maps[maps_cur][map_lengths[maps_cur]-1] = new_range_map;
+
+        memset(line, 0, line_buf_length);
+    }
+
+    maps_cur = 0;
+
+    uint64_t lowest_loc_n = UINT64_MAX;
+
+    for (size_t i = 0; i < seed_ranges_len; i += 2) {
+        #pragma omp shared(lowest_loc_n)
+        #pragma omp parallel for
+        for (uint64_t r = seed_ranges[i]; r < seed_ranges[i] + seed_ranges[i+1]; ++r) {
+            uint64_t seed = r;
+
+            for (size_t j = 0; j < MAPS_LEN; ++j) {
+                for (size_t n = 0; n < map_lengths[j]; ++n) {
+                    if (seed >= maps[j][n].src && seed <= maps[j][n].src + maps[j][n].rng) {
+                        seed = maps[j][n].dst + (seed - maps[j][n].src);
+                        break;
+                    }
+                }
+            }
+
+            if (seed < lowest_loc_n)
+                lowest_loc_n = seed;
+        }
+    }
+
+
+    free(seed_ranges);
+
+    for (size_t i = 0; i < MAPS_LEN; ++i)
+        free(maps[i]);
+
+    printf("%lu\n", lowest_loc_n);
+
+    return 0;
+}
+
+uint64_t parse_number(char *end) {
+    uint64_t num = 0;
+
+    for (size_t n = 1;; n *= 10) {
+        if (*end>>4 != 0x3)
+            break;
+        num += (*end&0xf) * n;
+        --end;
+    }
+
+    return num;
+}
\ No newline at end of file
diff --git a/test b/test
index 2c68456..0e9d7c2 100755
--- a/test
+++ b/test
@@ -16,4 +16,7 @@ echo "Day 3 with test data part 1 $(test_case 3 1 "test" "4361"), and part 2 $(t
 echo "Day 3 with my data part 1 $(test_case 3 1 "my" "550934"), and part 2 $(test_case 3 2 "my" "81997870").";
 
 echo "Day 4 with test data part 1 $(test_case 4 1 "test" "13"), and part 2 $(test_case 4 2 "test" "30").";
-echo "Day 4 with my data part 1 $(test_case 4 1 "my" "21959"), and part 2 $(test_case 4 2 "my" "5132675").";
\ No newline at end of file
+echo "Day 4 with my data part 1 $(test_case 4 1 "my" "21959"), and part 2 $(test_case 4 2 "my" "5132675").";
+
+echo "Day 5 with test data part 1 $(test_case 5 1 "test" "35"), and part 2 $(test_case 5 2 "test" "46").";
+# echo "Day 5 with my data part 1 $(test_case 5 1 "my" "379811651"), and part 2 $(test_case 5 2 "my" "27992443").";
\ No newline at end of file