1 files changed, 81 insertions, 0 deletions
diff --git a/Advent-of-Code-2020/AOC-1/main.c b/Advent-of-Code-2020/AOC-1/main.c
new file mode 100644
index 0000000..070642f
--- /dev/null
+++ b/Advent-of-Code-2020/AOC-1/main.c
@@ -0,0 +1,81 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#if 0
+  #define PFILE "sample.txt"
+  #define A_CAP 6
+#else
+  #define PFILE "input.txt"
+  #define A_CAP 200
+#endif
+
+int ints[A_CAP];
+
+void PrintInts()
+{
+  for(int i=0; i<A_CAP; i++)
+    printf("%d\n", ints[i]);
+}
+
+void Parse()
+{
+  // Parse
+  char ch;
+  FILE *fp;
+  fp = fopen(PFILE, "r");
+
+  int i = 0;
+  int n = 0;
+  char *int_str = malloc(sizeof(char)*5);
+  while((ch = fgetc(fp)) != EOF)
+  {
+    if(ch == '\n')
+    {
+      ints[i] = atoi(int_str);
+      i += 1;
+      n = 0;
+      memset(int_str, 0, sizeof(char)*5);
+      continue;
+    }
+
+    int_str[n] = ch;
+    n += 1;
+  }
+
+  assert(i == A_CAP);
+
+  free(int_str);
+  fclose(fp);
+}
+
+void Part1()
+{
+  Parse();
+  
+  // Check
+  for(int i=1; i<A_CAP; i++)
+    for(int j=i; j<A_CAP; j++)
+      if((ints[i-1] + ints[j]) == 2020)
+	printf("RESULT-1: %llu\n", ints[i-1] * ints[j]);
+}
+
+void Part2()
+{
+  Parse();
+
+  // Check
+  for(int i=2; i<A_CAP; i++)
+    for(int j=i; j<A_CAP; j++)
+      for(int k=j; k<A_CAP; k++)
+	if((ints[i-2] + ints[j-1] + ints[k]) == 2020)
+	  printf("RESULT-2: %llu\n", ints[i-2] * ints[j-1] * ints[k]);
+}
+
+int main(void)
+{
+  Part1();
+  Part2();
+  return 0;
+}