1 files changed, 80 insertions, 0 deletions
diff --git a/Advent-of-Code-2020/AOC-6/main.c b/Advent-of-Code-2020/AOC-6/main.c
new file mode 100755
index 0000000..7fa135e
--- /dev/null
+++ b/Advent-of-Code-2020/AOC-6/main.c
@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if 0
+#define PART_1
+#else
+#define PART_2
+#endif
+
+#if 0
+#define FILE_PATH "example.txt"
+#else
+#define FILE_PATH "input.txt"
+#endif
+
+int q_answ = 0;
+
+void parse()
+{
+    FILE *fp = fopen(FILE_PATH, "r");
+    if(!fp) {
+        fprintf(stderr, "ERROR: Could not open file: %s", FILE_PATH);
+        exit(EXIT_FAILURE);
+    }
+
+    char questions[26] = "abcdefghijklmnopqrstuvwxyz";
+    int answered[26] = {0};
+
+#ifdef PART_2
+    int ppl_in_group = 0;
+#endif
+
+    char line[32];
+    while(fgets(line, sizeof(line), fp) != NULL)
+    {
+        if(line[0] == '\n' || strncmp(line, "EOF", 3) == 0) {
+            for(int i = 0; i < 26; i++) {
+            #ifdef PART_1
+                q_answ += answered[i];
+            #endif
+
+            #ifdef PART_2
+                if(answered[i] == ppl_in_group)
+                     q_answ++;
+            #endif
+            }
+
+        #ifdef PART_2
+            ppl_in_group = 0;
+        #endif
+            memset(answered, 0, sizeof(answered));
+            continue;
+        }
+
+        #ifdef PART_2
+            ppl_in_group++;
+        #endif
+
+        for(int i = 0; i < strlen(line); i++)
+            for(int j = 0; j < 26; j++)
+                if(line[i] == questions[j]) {
+                #ifdef PART_1
+                    answered[j] = 1;
+                #endif
+                #ifdef PART_2
+                    answered[j]++;
+                #endif
+                }
+    }
+
+    fclose(fp);
+}
+
+int main(void)
+{
+    parse();
+    printf("%d questions answered\n", q_answ);
+    return 0;
+}