Day4

day4/overlap.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BUFFER_SIZE 64
+#define max(a,b) (a >= b ? a : b)
+#define min(a,b) (a <= b ? a : b)
+
+int overlap(int, int, int, int);
+
+int main() {
+    char buf[BUFFER_SIZE], *p, c;
+    int min1, max1, min2, max2, overlap_count, sum = 0, sum2 = 0;
+    memset(buf, 0, BUFFER_SIZE);
+    p = buf;
+
+    while ((c = getchar()) != EOF) {
+        *p++ = c;
+        if (c == '\n') {
+            sscanf(buf, "%i-%i,%i-%i", &min1, &max1, &min2, &max2);
+
+            overlap_count = overlap(min1, max1, min2, max2);
+
+            if (overlap_count == max1 - min1 + 1 || overlap_count == max2 - min2 + 1) {
+                sum += 1;
+            }
+
+            if (overlap_count > 0) {
+                sum2 += 1;
+            }
+
+            memset(buf, 0, BUFFER_SIZE);
+            p = buf;
+        }
+    }
+
+    printf("%i\n", sum);
+    printf("%i\n", sum2);
+}
+
+int overlap(int min1, int max1, int min2, int max2) {
+    if (max1 < min2 || max2 < min1)
+        return 0;
+
+    return min(max1, max2) - max(min1, min2) + 1;
+}