1 files changed, 41 insertions, 0 deletions
diff --git a/2020/02/part1.c b/2020/02/part1.c
new file mode 100644
index 0000000..11d955b
--- /dev/null
+++ b/2020/02/part1.c
@@ -0,0 +1,41 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool is_valid_password(char *pass, char *policy)
+{
+    int min = atoi(policy);
+    char *minP = strchr(policy, '-');
+    int max = atoi(++minP);
+    char c = *(strchr(minP, ' ') + 1);
+    char *p = pass;
+    int occ = 0;
+    do {
+        if (*p == c) {
+            occ++;
+        }
+    } while (*++p);
+
+    return occ >= min && occ <= max;
+}
+
+int main(int argc, char *argv[])
+{
+    FILE *file = fopen(argv[argc - 1], "r");
+    if (!file) {
+        return 1;
+    }
+
+    char buffer[128] = { 0 };
+    int valid = 0;
+    while (fgets(buffer, 128, file)) {
+        if (is_valid_password(strchr(buffer, ':') + 2, buffer)) {
+            valid++;
+        }
+    }
+
+    fclose(file);
+
+    printf("%i", valid);
+}