aoc

Advent of Code challenges
log files refs
aoc_2024_3_2.c (1259B)
      1#include <stdio.h>
      2#include <stdlib.h>
      3#include <stdbool.h>
      4#include <string.h>
      5#include <ctype.h>
      6
      7#define OPS_SIZE 1000
      8
      9typedef struct {
     10  int a;
     11  int b;
     12} op_t;
     13
     14long perform(char *data) {
     15  int len = strlen(data);
     16  int size = 0;
     17  op_t ops[OPS_SIZE];
     18  bool is_enabled = true;
     19  for (int i = 0; i < len;) {
     20    if (strncmp(data + i, "do()", 4) == 0) {
     21      is_enabled = true;
     22    }
     23    if (strncmp(data + i, "don't()", 7) == 0) {
     24      is_enabled = false;
     25    }
     26    // detect pattern: mul(\d,\d)
     27    // mul(
     28    if (strncmp(data + i, "mul(", 4) == 0) {
     29      i += 4;
     30      char *end = NULL;
     31      op_t *op = &ops[size];
     32      // \d
     33      if (!isdigit(data[i])) {
     34        continue;
     35      }
     36      op->a = strtol(data + i, &end, 10);
     37      i += end - (data + i);
     38      // ,
     39      if (data[i] != ',') {
     40        continue;
     41      }
     42      i++;
     43      // \d
     44      if (!isdigit(data[i])) {
     45        continue;
     46      }
     47      op->b = strtol(data + i, &end, 10);
     48      i += end - (data + i);
     49      // )
     50      if (data[i] != ')') {
     51        continue;
     52      }
     53      i++;
     54      if (is_enabled) {
     55        size++;
     56      }
     57      continue;
     58    }
     59    i++;
     60  }
     61  int sum = 0;
     62  for (int i = 0; i < size; i++) {
     63    op_t op = ops[i];
     64    sum += op.a * op.b;
     65  }
     66  return sum;
     67}