1 files changed, 128 insertions, 0 deletions
diff --git a/Advent-of-Code-2021/AOC-15/main.c b/Advent-of-Code-2021/AOC-15/main.c
new file mode 100644
index 0000000..c7e1157
--- /dev/null
+++ b/Advent-of-Code-2021/AOC-15/main.c
@@ -0,0 +1,128 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define min(a, b) (((a) < (b)) ? (a) : (b))
+
+#if 0
+  #define N 1
+#else
+  #define N 5
+#endif
+
+
+// part 2 doesnt work with input for some reason bruh
+#if 1
+  #define FILE_P "sample.txt"
+  #define T_CAP 10 * N
+  #define T_CAP_S 10
+#else
+  #define FILE_P "input.txt"
+  #define T_CAP 100 * N
+  #define T_CAP_S 100
+#endif
+
+int table[T_CAP][T_CAP];
+
+void ParseInput(char *filepath)
+{
+  char ch;
+  FILE *fp;
+  fp = fopen(filepath, "r");
+
+  if(fp == NULL)
+  {
+    fprintf(stderr, "ERROR: something with file idk fuck you");
+    exit(EXIT_FAILURE);
+  }
+
+  int i = 0;
+  int j = 0;
+  while((ch = fgetc(fp)) != EOF)
+  {
+    if(ch == '\n') { i += 1; j = 0; continue; }
+
+    table[i][j] = (ch - '0');
+    j += 1;
+  }
+  
+  fclose(fp);
+}
+
+void FindRisk()
+{
+  // dont add to total risk
+  table[0][0] = 0;
+  
+  for(int i=1; i<T_CAP; i++) table[i][0] += table[i-1][0];
+  for(int j=1; j<T_CAP; j++) table[0][j] += table[0][j-1];
+
+  for(int i=1; i<T_CAP; i++)
+  {
+    for(int j=1; j<T_CAP; j++)
+    {
+      table[i][j] += min(table[i][j-1], table[i-1][j]);
+    }
+  }
+
+}
+
+void Part1()
+{
+  ParseInput(FILE_P);
+  FindRisk();
+  printf("PART1: %d\n", table[T_CAP-1][T_CAP-1]); 
+}
+
+void ReconstructMap()
+{
+  for(int j=0; j<T_CAP_S; j++)
+    for(int n=T_CAP_S; n<T_CAP; n+=T_CAP_S)
+      for(int i=0; i<T_CAP_S; i++)
+      {
+	if(table[i+n-T_CAP_S][j] != 9)
+	  table[i+n][j] = table[i+n-T_CAP_S][j] + 1;
+	else
+	  table[i+n][j] = 1;
+      }
+
+  for(int i=0; i<T_CAP; i++)
+    for(int n=T_CAP_S; n<T_CAP; n+=T_CAP_S)
+      for(int j=0; j<T_CAP_S; j++)
+      {
+	if(table[i][j+n-T_CAP_S] != 9)
+	  table[i][j+n] = table[i][j+n-T_CAP_S] + 1;
+	else
+	  table[i][j+n] = 1;
+      }
+}
+
+void Part2()
+{
+  ParseInput(FILE_P);
+  ReconstructMap();
+  FindRisk();
+  printf("PART2: %d\n", table[T_CAP-1][T_CAP-1]);
+}
+
+void PrintTable()
+{
+  for(int i=0; i<T_CAP; i++)
+  {
+    for(int j=0; j<T_CAP; j++)
+    {
+      printf("%d", table[i][j]);
+    }
+    printf("\n");
+  }
+}
+
+int main(void)
+{
+  memset(table, 0, sizeof(table));
+  //  Part1();
+  Part2();
+ 
+  return 0;
+}
+