/* aoc-c.c: Advent of Code 2019, day 7 parts 1 & 2 * * Copyright (C) 2022 Bruno Raoult ("br") * Licensed under the GNU General Public License v3.0 or later. * Some rights reserved. See COPYING. * * You should have received a copy of the GNU General Public License along with this * program. If not, see . * * SPDX-License-Identifier: GPL-3.0-or-later */ #include #include #include #include #include "br.h" #include "bits.h" #include "debug.h" #include "list.h" #include "pool.h" /* operators codes */ typedef enum { ADD = 1, MUL = 2, /* CALC: add and mult */ INP = 3, OUT = 4, /* I/O: input and output value */ JMP_T = 5, JMP_F = 6, /* JUMPS: jump if true / if false */ SET_LT = 7, SET_EQ = 8, /* COND SETS: set if true/false */ HLT = 99 /* HALT */ } opcode_t; /** * ops - array of op-codes, mnemo, and number of parameters * @op: An integer, the opcode * @length: Next instruction offset */ typedef struct { int op; u8 length; } ops_t; typedef struct input { int val; struct list_head list; } input_t; #define MAXOPS 1024 typedef struct { int length; /* total program length */ int cur; /* current position */ struct list_head input; /* process input queue */ int mem [MAXOPS]; /* should really be dynamic */ } program_t; static ops_t ops[] = { [ADD] = { ADD, 4 }, [MUL] = { MUL, 4 }, [INP] = { INP, 2 }, [OUT] = { OUT, 2 }, [JMP_T] = { JMP_T, 3 }, [JMP_F] = { JMP_F, 3 }, [SET_LT] = { SET_LT, 4 }, [SET_EQ] = { SET_EQ, 4 }, [HLT] = { HLT, 1 } }; static int _flag_pow10[] = {1, 100, 1000, 10000}; #define OP(p, n) ((p->mem[n]) % 100) #define ISDIRECT(p, n, i) ((((p->mem[n]) / _flag_pow10[i]) % 10)) #define DIRECT(p, i) ((p)->mem[i]) #define INDIRECT(p, i) (DIRECT(p, DIRECT(p, i))) #define peek(p, n, i) (ISDIRECT(p, n, i)? DIRECT(p, n + i): INDIRECT(p, n + i)) #define poke(p, n, i, val) do { \ INDIRECT(p, n + i) = val; } \ while (0) static pool_t *pool_input; static __always_inline int prg_add_input(program_t *prg, int in) { input_t *input = pool_get(pool_input); input->val = in; list_add_tail(&input->list, &prg->input); return in; } static __always_inline int prg_get_input(program_t *prg, int *out) { input_t *input = list_first_entry_or_null(&prg->input, input_t, list); if (!input) return 0; *out = input->val; list_del(&input->list); pool_add(pool_input, input); return 1; } /** * permute - get next permutation of an array of integers * @len: length of array * @array: address of array * * Algorithm: lexicographic permutations * https://en.wikipedia.org/wiki/Permutation#Generation_in_lexicographic_order * Before the initial call, the array must be sorted (e.g. 0 2 3 5) * * Return: 1 if next permutation was found, 0 if no more permutation. * */ static int permute_next(int len, int *array) { int k, l; /* 1. Find the largest index k such that a[k] < a[k + 1] */ for (k = len - 2; k >= 0 && array[k] >= array[k + 1]; k--) ; /* No more permutations */ if (k < 0) return 0; /* 2. Find the largest index l greater than k such that a[k] < a[l] */ for (l = len - 1; array[l] <= array[k]; l--) ; /* 3. Swap the value of a[k] with that of a[l] */ swap(array[k], array[l]); /* 4. Reverse sequence from a[k + 1] up to the final element */ for (l = len - 1, k++; k < l; k++, l--) swap(array[k], array[l]); return 1; } static int run(program_t *p, int *end) { int out = -1; while (1) { int op = OP(p, p->cur), cur = p->cur, input; if (!(ops[op].op)) { fprintf(stderr, "PANIC: illegal instruction %d at %d.\n", op, p->cur); return -1; } switch (op) { case ADD: poke(p, p->cur, 3, peek(p, p->cur, 1) + peek(p, p->cur, 2)); break; case MUL: poke(p, p->cur, 3, peek(p, p->cur, 1) * peek(p, p->cur, 2)); break; case INP: if (prg_get_input(p, &input)) poke(p, p->cur, 1, input); else /* we need an input which is not yet avalable, so we need * to put the program in "waiting mode": We stop it (and * return output value) without setting end flag. */ goto sleep; break; case OUT: out = peek(p, p->cur, 1); break; case JMP_T: if (peek(p, p->cur, 1)) p->cur = peek(p, p->cur, 2); break; case JMP_F: if (!peek(p, p->cur, 1)) p->cur = peek(p, p->cur, 2); break; case SET_LT: poke(p, p->cur, 3, peek(p, p->cur, 1) < peek(p, p->cur, 2) ? 1: 0); break; case SET_EQ: poke(p, p->cur, 3, peek(p, p->cur, 1) == peek(p, p->cur, 2) ? 1: 0); break; case HLT: *end = 1; sleep: return out; } if (p->cur == cur) p->cur += ops[op].length; } } static void parse(program_t *prog) { while (scanf("%d%*c", &prog->mem[prog->length++]) > 0) ; } static int usage(char *prg) { fprintf(stderr, "Usage: %s [-d debug_level] [-p part] [-i input]\n", prg); return 1; } int main(int ac, char **av) { int phase1[] = {0, 1, 2, 3, 4}, phase2[] = {5, 6, 7, 8, 9}, *phase; int opt, max = 0, part = 1; program_t p = { 0 }, prg[5]; while ((opt = getopt(ac, av, "d:p:o:")) != -1) { switch (opt) { case 'd': debug_level_set(atoi(optarg)); break; case 'o': for (ulong i = 0; i < strlen(optarg); ++i) phase1[i] = optarg[i] - '0'; break; case 'p': /* 1 or 2 */ part = atoi(optarg); if (part < 1 || part > 2) return usage(*av); break; default: return usage(*av); } } pool_input = pool_create("input", 128, sizeof(input_t)); if (optind < ac) return usage(*av); phase = part == 1? phase1: phase2; parse(&p); do { int out = 0, end = 0; /* reset programs initial state, and add phase to their input */ for (unsigned i = 0; i < ARRAY_SIZE(prg); ++i) { prg[i] = p; INIT_LIST_HEAD(&prg[i].input); prg_add_input(&prg[i], phase[i]); } /* run the 5 processes in order (0, 1, 2, 3, 4, 0, 1, etc...), * until end flag is set by the process 4 (HLT instruction) */ while (!end) { for (int i = 0; i < 5; ++i) { /* add last process output in current process input queue */ prg_add_input(&prg[i], out); out = run(&prg[i], &end); } } max = max(max, out); } while (permute_next(5, phase)); printf("%s : res=%d\n", *av, max); pool_destroy(pool_input); exit(0); }