2022-day2.c

#include <stdio.h>
#include <stdlib.h>

enum throw
{
	ROCK,
	PAPER,
	SCISSORS
};

enum targ
{
	LOSE,
	DRAW,
	WIN
};

static int p2(enum throw op, enum targ target)
{
	switch(op)
	{
		case ROCK:
			if(target == WIN)
				return 6 + PAPER + 1;
			if(target == DRAW)
				return 3 + ROCK + 1;
			if(target == LOSE)
				return 0 + SCISSORS + 1;
		break;
		case PAPER:
			if(target == WIN)
				return 6 + SCISSORS + 1;
			if(target == DRAW)
				return 3 + PAPER + 1;
			if(target == LOSE)
				return 0 + ROCK + 1;
		break;
		case SCISSORS:
			if(target == WIN)
				return 6 + ROCK + 1;
			if(target == DRAW)
				return 3 + SCISSORS + 1;
			if(target == LOSE)
				return 0 + PAPER + 1;
		break;
	}
}

int main(void)
{
	FILE *f;
	char line[1024];
	long sum = 0, sum2 = 0;

	f = fopen("day2.txt", "r");

	while(1)
	{
                int o, m, s;

		if(!fgets(line, 128, f))
			break;

		o = line[0] - 'A';
		m = line[2] - 'X';

		sum += ((o==m)+(((o^2)-!!(o^2)==m)<<1))*3+m+1;
		sum2 += p2(o, m);
	}

	printf("Final sum: %ld, %ld\n", sum, sum2);
	return 0;
}