From: Mart Lubbers <mart@martlubbers.net>
Date: Thu, 16 Dec 2021 07:35:09 +0000 (+0100)
Subject: day 16
X-Git-Url: https://git.martlubbers.net/?a=commitdiff_plain;h=90f8da4f146227effae7a9b6fc694731a7329fd9;p=advent21.git

day 16
---

diff --git a/16.txt b/16.txt
new file mode 100644
index 0000000..b60e296
--- /dev/null
+++ b/16.txt
@@ -0,0 +1 @@
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
diff --git a/16a.c b/16a.c
new file mode 100644
index 0000000..75b3404
--- /dev/null
+++ b/16a.c
@@ -0,0 +1,78 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+char *hex2bin[] = { ['0'] = "0000" , ['1'] = "0001" , ['2'] = "0010" , ['3'] = "0011" , ['4'] = "0100" , ['5'] = "0101" , ['6'] = "0110" , ['7'] = "0111" , ['8'] = "1000" , ['9'] = "1001" , ['A'] = "1010" , ['B'] = "1011" , ['C'] = "1100" , ['D'] = "1101" , ['E'] = "1110" , ['F'] = "1111", ['\n'] = "0000"};
+
+struct stream {
+	int pos;
+	char *buf;
+};
+
+int next(struct stream *f)
+{
+	if (*f->buf == '\0') {
+		int c = getchar();
+		if (c == EOF) {
+			printf("EOF\n");
+			exit(1);
+		}
+		f->buf = hex2bin[c];
+	}
+	int r =*f->buf == '1' ? 1 : 0;
+	f->buf++;
+	f->pos++;
+	return r;
+}
+
+int bin2int(struct stream *f, int n)
+{
+	int r = 0;
+	for (int i = 0; i<n; i++)
+		r = 2*r+next(f);
+	return r;
+}
+
+int parse_packet(struct stream *f)
+{
+	int packetversion = bin2int(f, 3);
+	int packettype = bin2int(f, 3);
+
+	switch (packettype) {
+	//Literal value
+	case 4: {
+		int num = 0;
+		while (next(f) == 1) {
+			num = num*16+bin2int(f, 4);
+		}
+		num = num*16+bin2int(f, 4);
+		break;
+	}
+	default: {
+		int lengthtypeid = next(f);
+
+		//length is 15
+		if (lengthtypeid == 0) {
+			int lengthsubpackets = bin2int(f, 15);
+			int oldpos = f->pos;
+
+			while (f->pos - oldpos < lengthsubpackets)
+				packetversion += parse_packet(f);
+		} else {
+			int numsubpackets = bin2int(f, 11);
+			for (int i = 0; i<numsubpackets; i++)
+				packetversion += parse_packet(f);
+		}
+		break;
+	}}
+	return packetversion;
+}
+
+int main()
+{
+	struct stream f = {.pos=0, .buf=""};
+
+	int r = parse_packet(&f);
+	printf("r: %d\n", r);
+}
diff --git a/16b.c b/16b.c
new file mode 100644
index 0000000..4310a7b
--- /dev/null
+++ b/16b.c
@@ -0,0 +1,108 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+
+char *hex2bin[] =
+	{ ['0'] = "0000", ['1'] = "0001", ['2'] = "0010", ['3'] = "0011"
+	, ['4'] = "0100", ['5'] = "0101", ['6'] = "0110", ['7'] = "0111"
+	, ['8'] = "1000", ['9'] = "1001", ['A'] = "1010", ['B'] = "1011"
+	, ['C'] = "1100", ['D'] = "1101", ['E'] = "1110", ['F'] = "1111"
+	, ['\n'] = "0000"};
+
+struct stream { int pos; char *buf; };
+
+int next(struct stream *f)
+{
+	int r;
+	if (*f->buf == '\0') {
+		if ((r = getchar()) == EOF) {
+			printf("EOF\n");
+			exit(1);
+		}
+		f->buf = hex2bin[r];
+	}
+	r =*(f->buf++) == '1' ? 1 : 0;
+	f->pos++;
+	return r;
+}
+
+unsigned long bin2int(struct stream *f, int n)
+{
+	unsigned long r = 0;
+	for (int i = 0; i<n; i++)
+		r = 2*r+next(f);
+	return r;
+}
+
+unsigned long parse_packet(struct stream *f)
+{
+	int packetversion  __attribute__((unused)) = bin2int(f, 3);
+	int packettype = bin2int(f, 3);
+	unsigned long result = 0;
+
+	//literal
+	if (packettype == 4) {
+		while (next(f) == 1)
+			result = result*16+bin2int(f, 4);
+		result = result*16+bin2int(f, 4);
+	//operator
+	} else {
+		int lengthtypeid = next(f);
+		unsigned long packets[100] = {0};
+		int npackets = 0;
+
+		//number of bits
+		if (lengthtypeid == 0) {
+			int lengthsubpackets = bin2int(f, 15);
+			int oldpos = f->pos;
+			while (f->pos - oldpos < lengthsubpackets)
+				packets[npackets++] = parse_packet(f);
+		//number of packets
+		} else {
+			npackets = bin2int(f, 11);
+			for (int i = 0; i<npackets; i++)
+				packets[i] = parse_packet(f);
+		}
+
+		//sum
+		if (packettype == 0) {
+			for (int i = 0; i<npackets; i++)
+				result += packets[i];
+		//product
+		} else if (packettype == 1) {
+			result = 1;
+			for (int i = 0; i<npackets; i++)
+				result *= packets[i];
+		//minimum
+		} else if (packettype == 2) {
+			result = ULONG_MAX;
+			for (int i = 0; i<npackets; i++)
+				result = packets[i] < result ? packets[i] : result;
+		//maximum
+		} else if (packettype == 3) {
+			result = 0;
+			for (int i = 0; i<npackets; i++)
+				result = packets[i] > result ? packets[i] : result;
+		//greater than
+		} else if (packettype == 5) {
+			result = packets[0] > packets[1];
+		//less than
+		} else if (packettype == 6) {
+			result = packets[0] < packets[1];
+		//equal to
+		} else if (packettype == 7) {
+			result = packets[0] == packets[1];
+		//unknown
+		} else {
+			fprintf(stderr, "unknown operator: %d\n", packettype);
+			exit(1);
+		}
+	}
+	return result;
+}
+
+int main()
+{
+	struct stream f = {.pos=0, .buf=""};
+	printf("r: %lu\n", parse_packet(&f));
+}
diff --git a/16e.txt b/16e.txt
new file mode 100644
index 0000000..3f0eda1
--- /dev/null
+++ b/16e.txt
@@ -0,0 +1 @@
+D2FE28
diff --git a/16e2.txt b/16e2.txt
new file mode 100644
index 0000000..a7f8f25
--- /dev/null
+++ b/16e2.txt
@@ -0,0 +1 @@
+38006F45291200
diff --git a/16e3.txt b/16e3.txt
new file mode 100644
index 0000000..bcc798c
--- /dev/null
+++ b/16e3.txt
@@ -0,0 +1 @@
+EE00D40C823060
diff --git a/16e4.txt b/16e4.txt
new file mode 100644
index 0000000..0d2cbff
--- /dev/null
+++ b/16e4.txt
@@ -0,0 +1 @@
+8A004A801A8002F478
diff --git a/16e5.txt b/16e5.txt
new file mode 100644
index 0000000..ed3b78a
--- /dev/null
+++ b/16e5.txt
@@ -0,0 +1 @@
+620080001611562C8802118E34
diff --git a/16e6.txt b/16e6.txt
new file mode 100644
index 0000000..827e51b
--- /dev/null
+++ b/16e6.txt
@@ -0,0 +1 @@
+C0015000016115A2E0802F182340
diff --git a/16e7.txt b/16e7.txt
new file mode 100644
index 0000000..0a1278e
--- /dev/null
+++ b/16e7.txt
@@ -0,0 +1 @@
+A0016C880162017C3686B18A3D4780