Day2

day2/rockpaperscissors.c

@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BUFFER_SIZE 5
+
+#define score_play(p) (p - 'W')
+#define win(o, m) (o == m ? 3 : ((o - m == 1 || o - m == -2) ? 0 : 6))
+#define score_game(o, m) (score_play(m) + win((o - 'A'), (m - 'X')))
+
+int main() {
+    char buf[BUFFER_SIZE], *p, c, opponent, me;
+    memset(buf, 0, BUFFER_SIZE);
+    p = buf;
+    unsigned score = 0;
+
+    while ((c = getchar()) != EOF) {
+        *p++ = c;
+        if (c == '\n') {
+            sscanf(buf, "%c %c", &opponent, &me);
+            score += score_game(opponent, me);
+            printf("%u\n", score);
+
+            memset(buf, 0, BUFFER_SIZE);
+            p = buf;
+        }
+    }
+
+    printf("%u\n", score);
+}

day2/rockpaperscissors2.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BUFFER_SIZE 5
+
+#define score_play(p) (p - 'W')
+#define win(o, m) (o == m ? 3 : ((o - m == 1 || o - m == -2) ? 0 : 6))
+#define score_game(o, m) (score_play(m) + win((o - 'A'), (m - 'X')))
+#define win_strategy(o) (o - 'A' + 1 > 2 ? 'X' : o - 'A' + 1 + 'X')
+#define lose_strategy(o) (o - 'A' - 1 < 0 ? 'Z' : o - 'A' - 1 + 'X')
+#define draw_strategy(o) (o - 'A' + 'X')
+
+int main() {
+    char buf[BUFFER_SIZE], *p, c, opponent, result, me;
+    memset(buf, 0, BUFFER_SIZE);
+    p = buf;
+    unsigned score = 0;
+
+    while ((c = getchar()) != EOF) {
+        *p++ = c;
+        if (c == '\n') {
+            sscanf(buf, "%c %c", &opponent, &result);
+            me = result == 'X' ? lose_strategy(opponent) : (result == 'Y' ? draw_strategy(opponent) : win_strategy(opponent));
+            score += score_game(opponent, me);
+
+            memset(buf, 0, BUFFER_SIZE);
+            p = buf;
+        }
+    }
+
+    printf("%u\n", score);
+}