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day 16 part 2 (before code cleanup)

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Bruno Raoult
2021-12-21 11:57:04 +01:00
parent 50963c233b
commit bdfad93f4a
2 changed files with 87 additions and 79 deletions
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6
2021/day16/README.txt
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@@ -93,8 +93,6 @@ Here are a few more examples of hexadecimal-encoded transmissions:
Decode the structure of your hexadecimal-encoded BITS transmission; what do you get if you add up the version numbers in all packets?
Your puzzle answer was 923.
The first half of this puzzle is complete! It provides one gold star: *
--- Part Two ---
Now that you have the structure of your transmission decoded, you can calculate the value of the expression it represents.
@@ -123,3 +121,7 @@ For example:
9C0141080250320F1802104A08 produces 1, because 1 + 3 = 2 * 2.
What do you get if you evaluate the expression represented by your hexadecimal-encoded BITS transmission?
Your puzzle answer was 258888628940.
Both parts of this puzzle are complete! They provide two gold stars: **

160
2021/day16/aoc-c.c
View File

@@ -23,17 +23,17 @@
#include "bits.h"
#include "list.h"
#define MAX_SUBPACKETS 1024
#define TYPE_SUM 0
#define TYPE_PRODUCT 1
#define TYPE_MIN 2
#define TYPE_MAX 3
#define TYPE_VALUE 4
#define TYPE_GREATER 5
#define TYPE_LESS 6
#define TYPE_EQUAL 7
#define TYPE_VAL 4
struct packet {
u8 version;
u8 type;
u64 value;
};
static u64 totversions;
#define MAX_STACK 128 /* max stack for operators input */
static u64 totversions; /* sum of versions */
static u64 bitval(char *p, int length)
{
@@ -41,9 +41,7 @@ static u64 bitval(char *p, int length)
for (; length; length--, p++) {
u8 b = *p -'0';
val += b << (length - 1);
//printf("%c -> %d, %lu\n", *p, b, val);
}
//printf("%lu\n", val);
return val;
}
@@ -54,63 +52,89 @@ static u64 decode_value(char *bits, char **end)
for (u64 tmp = 16; tmp & 16; bits += 5) {
tmp = bitval(bits, 5);
val = val << 4 | (tmp & 15);
//printf("bits =%5s tmp=%lu xor=%lu val=%lu\n", bits, tmp, tmp & 15, val);
}
*end = bits;
return val;
}
int weight[] = {
['B'] = 0, ['C'] = 1, ['F'] = 2,
['H'] = 3, ['K'] = 4, ['N'] = 5, ['O'] = 6,
['P'] = 7, ['S'] = 8, ['V'] = 9
};
static struct packet decode(char *start, char **end)
static s64 decode(char *start, char **end)
{
struct packet packet;
char *cur;
s64 count;
u8 type;
s64 count, result = 0;
s64 stack[MAX_STACK];
int nstack = 0;
//printf("decode(%.4s...)\n", start);
packet.version = bitval(start, 3);
totversions += packet.version;
packet.type = bitval(start + 3, 3);
log_f(3, "[%.6s...] version=%d type=%d\n", start, packet.version, packet.type);
cur = start + 6;
switch (packet.type) {
case TYPE_VAL:
packet.value = decode_value(cur, end);
printf("val = %lu len=%lu\n", packet.value, *end - cur);
totversions += bitval(start, 3); /* decode version & type */
type = bitval(start + 3, 3);
start += 6;
if (type == TYPE_VALUE)
return decode_value(start, end);
switch (*start++) {
case '0':
count = bitval(start, 15);
start += 15;
*end = start;
log(3, "nbits = %lu\n", count);
while ((*end - start) < count) {
stack[nstack++] = decode(*end, end);
//log(3, " end - start = %lu\n", *end - start);
log(3, " stack %d = %ld\n", nstack - 1, stack[nstack - 1]);
}
break;
default:
switch (*cur++) {
case '0':
count = bitval(cur, 15);
cur += 15;
*end = cur;
printf("nbits = %lu\n", count);
while ((*end - cur) < count) {
decode(*end, end);
printf(" end - cur = %lu\n", *end - cur);
}
break;
case '1':
count = bitval(cur, 11);
cur += 11;
*end = cur;
printf("npackets = %ld\n", count);
while (count--) {
decode(*end, end);
printf(" count = %ld\n", count);
}
case '1':
count = bitval(start, 11);
start += 11;
*end = start;
log(3, "npackets = %ld\n", count);
while (count--) {
stack[nstack++] = decode(*end, end);
log(3, " stack %d = %ld\n", nstack - 1, stack[nstack - 1]);
}
}
switch (type) {
case TYPE_SUM:
log(3, "OP=sum\n");
while (--nstack > -1)
result += stack[nstack];
break;
case TYPE_PRODUCT:
result = 1; /* forgot this one ;-) */
log(3, "OP=mult\n");
while (--nstack > -1)
result *= stack[nstack];
break;
case TYPE_MIN:
result = INT64_MAX;
log(3, "OP=min\n");
while (--nstack > -1)
if (stack[nstack] < result)
result = stack[nstack];
break;
case TYPE_MAX:
log(3, "OP=max\n");
while (--nstack > -1)
if (stack[nstack] > result)
result = stack[nstack];
break;
case TYPE_GREATER:
log(3, "OP=gt\n");
result = stack[0] > stack[1]? 1: 0;
break;
case TYPE_LESS:
log(3, "OP=le\n");
result = stack[0] < stack[1]? 1: 0;
break;
case TYPE_EQUAL:
log(3, "OP=eq\n");
result = stack[0] == stack[1]? 1: 0;
}
//log_f(3, "bin=[%s] version=%d type=%d\n", bits, version, type);
//log_f(3, "[%s] version=%d type=%d\n", start, packet.version, packet.type);
return packet;
//log_f(3, "[%s] version=%d type=%d\n", start, version, type);
return result;
}
/* read BITS data
@@ -139,24 +163,6 @@ free:
return bits;
}
/*
static u32 doit()
{
return 1;
}
static u32 part1()
{
return doit();
}
static u32 part2()
{
return doit();
}
*/
static int usage(char *prg)
{
fprintf(stderr, "Usage: %s [-d debug_level] [-p part]\n", prg);
@@ -187,8 +193,8 @@ int main(int ac, char **av)
buf = read_input();
decode(buf, &end);
printf("END: end=%lu sum_versions=%lu\n", end - buf, totversions);
s64 result = decode(buf, &end);
printf("END: end=%lu sum_versions=%lu result=%ld\n", end - buf, totversions, result);
//printf("%s : res=%u\n", *av, part == 1? part1(): part2());
exit (0);
}