Puzzle 2: Consolidate 2a/2b programs into `2` with `-p` option

Like the later puzzles

1 files changed, 128 insertions, 0 deletions

diff --git a/2.c b/2.c
new file mode 100644
index 0000000..0fcd959
--- /dev/null
+++ b/2.c
@@ -0,0 +1,128 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+enum RPS {
+	ROCK,
+	PAPR,
+	SCRS,
+};
+
+
+enum RPS
+rps_beats(enum RPS rps)
+{
+	switch (rps) {
+	case ROCK: return SCRS;
+	case PAPR: return ROCK;
+	case SCRS: return PAPR;
+	}
+	return -1;
+}
+
+
+enum RPS
+rps_loses(enum RPS rps)
+{
+	switch (rps) {
+	case ROCK: return PAPR;
+	case PAPR: return SCRS;
+	case SCRS: return ROCK;
+	}
+	return -1;
+}
+
+
+int
+rps_pickscore(enum RPS rps)
+{
+	switch (rps) {
+	case ROCK: return 1;
+	case PAPR: return 2;
+	case SCRS: return 3;
+	}
+	return 0;
+}
+
+
+int
+rps_gamescore_b(enum RPS a, enum RPS b)
+{
+	if (b == a)
+		return 3;
+	if (rps_beats(b) == a)
+		return 6;
+	return 0;
+}
+
+
+int
+main(int argc, char ** argv)
+{
+	int part = 1, i;
+	char buf[BUFSIZ];
+	int score = 0;
+
+	while ((i = getopt(argc, argv, "p:")) != -1) {
+		switch (i) {
+		case 'p':
+			part = atoi(optarg);
+			break;
+
+		default:
+			return -1;
+		}
+	}
+
+	while (fgets(buf, sizeof(buf), stdin)) {
+		enum RPS a, b;
+
+		if (strlen(buf) != 4)
+			break;
+		switch (buf[0]) {
+		case 'A': a = ROCK; break;
+		case 'B': a = PAPR; break;
+		case 'C': a = SCRS; break;
+		default:
+			fprintf(stderr, "Unexpected input: %c (0x%2d)\n", buf[0], buf[0]);
+			return -1;
+		}
+		switch (part) {
+		case 1:
+			switch (buf[2]) {
+			case 'X': b = ROCK; break;
+			case 'Y': b = PAPR; break;
+			case 'Z': b = SCRS; break;
+			default:
+				fprintf(stderr, "Unexpected input: %c (0x%2d)\n", buf[2], buf[2]);
+				return -1;
+			}
+			break;
+
+		case 2:
+			switch (buf[2]) {
+			case 'X': b = rps_beats(a); break;
+			case 'Y': b = a; break;
+			case 'Z': b = rps_loses(a); break;
+			default:
+				fprintf(stderr, "Unexpected input: %c (0x%2d)\n", buf[2], buf[2]);
+				return -1;
+			}
+			break;
+
+		default:
+			fprintf(stderr, "Unexpected puzzle part %d\n", part);
+			return -1;
+		}
+
+		score += rps_pickscore(b) + rps_gamescore_b(a, b);
+	}
+
+	printf("Score: %d\n", score);
+
+	return 0;
+}
+