aoc

Advent of Code challenges
log files refs
aoc_2024_3_1.c (1022B)
      1#include <stdio.h>
      2#include <stdlib.h>
      3#include <string.h>
      4#include <ctype.h>
      5
      6#define OPS_SIZE 1000
      7
      8typedef struct {
      9  int a;
     10  int b;
     11} op_t;
     12
     13long perform(char *data) {
     14  int len = strlen(data);
     15  int size = 0;
     16  op_t ops[OPS_SIZE];
     17  for (int i = 0; i < len;) {
     18    // detect pattern: mul(\d,\d)
     19    // mul(
     20    if (strncmp(data + i, "mul(", 4) == 0) {
     21      i += 4;
     22      char *end = NULL;
     23      op_t *op = &ops[size];
     24      // \d
     25      if (!isdigit(data[i])) {
     26        continue;
     27      }
     28      op->a = strtol(data + i, &end, 10);
     29      i += end - (data + i);
     30      // ,
     31      if (data[i] != ',') {
     32        continue;
     33      }
     34      i++;
     35      // \d
     36      if (!isdigit(data[i])) {
     37        continue;
     38      }
     39      op->b = strtol(data + i, &end, 10);
     40      i += end - (data + i);
     41      // )
     42      if (data[i] != ')') {
     43        continue;
     44      }
     45      i++;
     46      size++;
     47      continue;
     48    }
     49    i++;
     50  }
     51  int sum = 0;
     52  for (int i = 0; i < size; i++) {
     53    op_t op = ops[i];
     54    sum += op.a * op.b;
     55  }
     56  return sum;
     57}