aoc23/02/part1.c

#include <stdio.h>
#include <stdlib.h>
#define MAX_LENGTH 165

char* skip_color(char* c) {
    switch (*c) {
        case 'r':
            return c + 3;
        case 'g':
            return c + 5;
        case 'b':
            return c + 4;
    }
    abort();
}


int main(void) {
    char buf[MAX_LENGTH];
    int game_num, cubes, sum;

    sum = 0;
    while (fgets(buf, MAX_LENGTH, stdin)) {
        char* c = buf;
        game_num = strtol(c + 5, &c, 10);  // +5 skips the "Game "

        while (*c != '\n') {
            cubes = strtol(c + 2, &c, 10);  // +2 skips ": ", ", ", or "; "
            c++;  // +1 skips the space
            if ((*c == 'r' && cubes > 12) ||
                (*c == 'g' && cubes > 13) ||
                (*c == 'b' && cubes > 14)) {
                game_num = 0;
            }
            c = skip_color(c);
        }
        sum += game_num;
    }
    printf("%d\n", sum);
    return 0;
}