From 1f75d7c9ebec207c8193754792076dc66eba9713 Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Tue, 19 Dec 2023 15:54:12 +0100
Subject: Added solutions for 15, 16, 17, 18 and 19

---
 2023/19/19a.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 2023/19/19a.c

(limited to '2023/19/19a.c')

diff --git a/2023/19/19a.c b/2023/19/19a.c
new file mode 100644
index 0000000..81ee535
--- /dev/null
+++ b/2023/19/19a.c
@@ -0,0 +1,87 @@
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define N 1000
+
+typedef struct { int64_t val[26]; } part_t;
+typedef struct { char v, comp, wnext[10]; int64_t b; } rule_t;
+typedef struct { char name[50]; int64_t n; rule_t r[100]; } workflow_t;
+
+int64_t nw, np, A;
+workflow_t w[N];
+part_t p[N];
+
+workflow_t readw(char *buf) {
+	workflow_t ret = {0};
+	for (int i = 0; *buf != '{'; buf++, i++)
+		ret.name[i] = *buf;
+	for (rule_t r; *buf != '}'; ret.r[ret.n++] = r) {
+		buf++;
+		memset(&r, 0, sizeof(r));
+		if (*(buf+1) == '<' || *(buf+1) == '>') {
+			r.v = *buf;
+			r.comp = *(buf+1);
+			r.b = atoll(buf+2);
+			while (*buf != ':') buf++;
+			buf++;
+		}
+		for (int i = 0; *buf != ',' && *buf != '}'; buf++, i++)
+			r.wnext[i] = *buf;
+	}
+	return ret;
+}
+
+part_t readp(char *buf) {
+	part_t p = {0};
+	while (*buf != '}') {
+		buf++;
+		p.val[*buf-'a'] = atoll(buf+2);
+		while(*buf != ',' && *buf != '}') buf++;
+	}
+	return p;
+}
+
+int64_t value(part_t p) {
+	return p.val['x'-'a'] + p.val['m'-'a'] + p.val['a'-'a'] + p.val['s'-'a'];
+}
+
+bool satisfy(part_t p, rule_t r) {
+	if (r.v == 0) return true;
+	int64_t val = p.val[r.v-'a'];
+	return r.comp == '<' ? (val < r.b) : (val > r.b);
+}
+
+workflow_t findw(char *name) {
+	for (int i = 0; i < nw; i++)
+		if (!strcmp(name, w[i].name))
+			return w[i];
+	printf("Error: workflow %s not found\n", name);
+	exit(1);
+}
+
+int main() {
+	char *buf, line[N];
+
+	for (nw = 0; *(buf = fgets(line, N, stdin)) != '\n'; nw++)
+		w[nw] = readw(buf);
+
+	for (np = 0; (buf = fgets(line, N, stdin)) != NULL; np++)
+		p[np] = readp(buf);
+
+	for (int i = 0; i < np; i++) {
+		workflow_t ww = findw("in");
+		for (rule_t r; ; ww = findw(r.wnext)) {
+			for (int64_t j = 0; !satisfy(p[i], r = ww.r[j]); j++) ;
+			if (!strcmp("A", r.wnext) || !strcmp("R", r.wnext)) {
+				A += value(p[i]) * (r.wnext[0] == 'A');
+				break;
+			}
+		}
+	}
+
+	printf("%" PRId64 "\n", A);
+	return 0;
+}
-- 
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