2017 day10 part1

3 files changed, 84 insertions, 1 deletions

diff --git a/src/2017/day10/aoc.cpp b/src/2017/day10/aoc.cpp
index 9ba0d48..1e8461e 100644
--- a/src/2017/day10/aoc.cpp
+++ b/src/2017/day10/aoc.cpp
@@ -2,5 +2,79 @@
 
 namespace aoc2017 {
 
-std::pair<int64_t, int64_t> day10(line_view) { return {0, 0}; }
+knot* make_knot(int n) {
+  knot* k = new knot;
+  k->val = 0;
+  k->next = k;
+  k->prev = k;
+  knot* last = k;
+  for (int i = 1; i < n; i++) {
+    knot* n = new knot;
+    n->val = i;
+    last->next = n;
+    n->prev = last;
+    last = n;
+    k->prev = last;
+    last->next = k;
+  }
+  return k;
+}
+
+static void print(knot* k) {
+  knot* n = k;
+  do {
+    printf("%d ", n->val);
+    n = n->next;
+  } while (n != k);
+  printf("\n");
+}
+
+void forward(knot** k, int n) {
+  knot* x = *k;
+  while (n-- > 0) {
+    x = x->next;
+  }
+  *k = x;
+}
+
+// static void reverse(knot* head, knot* tail) {
+// }
+
+static int get_number(const char** pp) {
+  int d{0};
+  const char* p = *pp;
+  while (*p >= '0' && *p <= '9') {
+    d = d * 10 + *p - '0';
+    p++;
+  }
+  *pp = p;
+  return d;
+}
+
+static void reverse(knot* head, int d) {}
+
+static void reverse_skip(knot** current, int d) {
+  static int skip = 0;
+
+  reverse(*current, d);
+  forward(current, d + skip);
+  skip += 1;
+}
+
+std::pair<int64_t, int64_t> day10(line_view file) {
+  knot* k = make_knot(256);
+
+  const char* p = file.line;
+  knot* current = k;
+  print(current);
+  while (p < file.line + file.length) {
+    int d = get_number(&p);
+    // printf("%d\n", d);
+    reverse_skip(&current, d);
+    p++;
+  }
+
+  print(current);
+  return {0, 0};
+}
 } // namespace aoc2017
diff --git a/src/2017/day10/aoc.h b/src/2017/day10/aoc.h
index 9fea13e..a4cdca8 100644
--- a/src/2017/day10/aoc.h
+++ b/src/2017/day10/aoc.h
@@ -3,5 +3,13 @@
 #include <vector>
 
 namespace aoc2017 {
+
+struct knot {
+  int val;
+  knot* next = nullptr;
+  knot* prev = nullptr;
+};
+
+
 std::pair<int64_t, int64_t> day10(line_view);
 }
diff --git a/src/2017/day10/input0 b/src/2017/day10/input0
index e69de29..cf15122 100644
--- a/src/2017/day10/input0
+++ b/src/2017/day10/input0
@@ -0,0 +1 @@
+3,4,1,5