2022 day17 part1

1 files changed, 88 insertions, 58 deletions

diff --git a/src/2022/day17/aoc.cpp b/src/2022/day17/aoc.cpp
index d7a1099..28a171f 100644
--- a/src/2022/day17/aoc.cpp
+++ b/src/2022/day17/aoc.cpp
@@ -4,7 +4,7 @@ namespace aoc2022 {
 
 static line_view moves;
 
-static uint8_t at(uint8_t r, int p) {
+static bool at(uint8_t r, int p) {
   // p 0..7
   uint8_t m = 0x01;
   while (p-- > 0)
@@ -14,14 +14,15 @@ static uint8_t at(uint8_t r, int p) {
 
 char next() {
   static int i{0};
-  i %= (moves.length - 1);
+  int x = i++ % (moves.length - 1);
   const char* p = moves.line;
-  return *(p + i++);
+  printf("%c at %d\n", *(p + x), x);
+  return *(p + x);
 }
 
-void print(const rock17& r) {
-  for (size_t i = r.rs.size(); i > 0; i--) {
-    uint8_t x = r.rs[i - 1];
+void print(std::vector<uint8_t>& rs) {
+  for (size_t i = rs.size(); i > 0; i--) {
+    uint8_t x = rs[i - 1];
     int c{6};
     while (c >= 0) {
       printf("%c", at(x, c) ? '#' : '.');
@@ -67,31 +68,23 @@ rock17 make_rock(int i) {
 rock17 right(rock17 r) {
   switch (r.type) {
   case r1:
-    if (at(r.rs[0], 0) == 0) {
-      r.rs[0] >>= 1;
-    }
+    r.rs[0] >>= 1;
     break;
   case r2:
   case r3:
-    if (at(r.rs[1], 0) == 0) {
-      r.rs[0] >>= 1;
-      r.rs[1] >>= 1;
-      r.rs[2] >>= 1;
-    }
+    r.rs[0] >>= 1;
+    r.rs[1] >>= 1;
+    r.rs[2] >>= 1;
     break;
   case r4:
-    if (at(r.rs[0], 0) == 0) {
-      r.rs[0] >>= 1;
-      r.rs[1] >>= 1;
-      r.rs[2] >>= 1;
-      r.rs[3] >>= 1;
-    }
+    r.rs[0] >>= 1;
+    r.rs[1] >>= 1;
+    r.rs[2] >>= 1;
+    r.rs[3] >>= 1;
     break;
   case r5:
-    if (at(r.rs[0], 0) == 0) {
-      r.rs[0] >>= 1;
-      r.rs[1] >>= 1;
-    }
+    r.rs[0] >>= 1;
+    r.rs[1] >>= 1;
     break;
   default:
     break;
@@ -102,37 +95,27 @@ rock17 right(rock17 r) {
 rock17 left(rock17 r) {
   switch (r.type) {
   case r1:
-    if (at(r.rs[0], 6) == 0) {
-      r.rs[0] <<= 1;
-    }
+    r.rs[0] <<= 1;
     break;
   case r2:
-    if (at(r.rs[1], 6) == 0) {
-      r.rs[0] <<= 1;
-      r.rs[1] <<= 1;
-      r.rs[2] <<= 1;
-    }
+    r.rs[0] <<= 1;
+    r.rs[1] <<= 1;
+    r.rs[2] <<= 1;
     break;
   case r3:
-    if (at(r.rs[0], 6) == 0) {
-      r.rs[0] <<= 1;
-      r.rs[1] <<= 1;
-      r.rs[2] <<= 1;
-    }
+    r.rs[0] <<= 1;
+    r.rs[1] <<= 1;
+    r.rs[2] <<= 1;
     break;
   case r4:
-    if (at(r.rs[0], 6) == 0) {
-      r.rs[0] <<= 1;
-      r.rs[1] <<= 1;
-      r.rs[2] <<= 1;
-      r.rs[3] <<= 1;
-    }
+    r.rs[0] <<= 1;
+    r.rs[1] <<= 1;
+    r.rs[2] <<= 1;
+    r.rs[3] <<= 1;
     break;
   case r5:
-    if (at(r.rs[0], 6) == 0) {
-      r.rs[0] <<= 1;
-      r.rs[1] <<= 1;
-    }
+    r.rs[0] <<= 1;
+    r.rs[1] <<= 1;
     break;
   default:
     break;
@@ -142,14 +125,51 @@ rock17 left(rock17 r) {
 
 bool collide(uint8_t r1, uint8_t r2) { return r1 & r2; }
 
+bool collide_left(std::vector<uint8_t>& rs1, std::vector<uint8_t>& rs2) {
+  for (size_t j = 0; j < rs1.size(); j++) {
+    for (int i = 6; i >= 0; i--) {
+      if (at(rs1[j], i) && (i == 6 || at(rs2[j + 1], i + 1))) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+bool collide_right(std::vector<uint8_t>& rs1, std::vector<uint8_t>& rs2) {
+  for (size_t j = 0; j < rs1.size(); j++) {
+    for (int i = 0; i <= 6; i++) {
+      if (at(rs1[j], i) && (i == 0 || at(rs2[j + 1], i - 1))) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+bool collide_down(std::vector<uint8_t>& rs1, std::vector<uint8_t>& rs2) { return collide(rs1[0], rs2[0]); }
+
 void merge(rock17& floor, rock17 r, int n) {
+  std::vector<uint8_t> room;
+  for (size_t i = floor.rs.size() - n - 1; room.size() < r.rs.size() + 1 && i < floor.rs.size(); i++) {
+    room.push_back(floor.rs[i]);
+  }
+
+  while (room.size() < r.rs.size() + 1) {
+    room.push_back(0x00);
+  }
+
   auto m = next();
-  printf("%c %d\n", m, r.type);
-  r = m == '>' ? right(r) : left(r);
+  if (m == '>' && !collide_right(r.rs, room)) {
+    // printf("%c %d\n", m, r.type);
+    r = right(r);
+  }
+  if (m == '<' && !collide_left(r.rs, room)) {
+    // printf("%c %d\n", m, r.type);
+    r = left(r);
+  }
 
-  uint8_t rt = floor.rs[floor.rs.size() - 1 - n];
-  uint8_t rh = r.rs[0];
-  if (!collide(rt, rh)) {
+  if (!collide_down(r.rs, room)) {
     merge(floor, r, n + 1);
   } else { // merge from n to last with r
     size_t m{0};
@@ -165,21 +185,31 @@ void merge(rock17& floor, rock17 r, int n) {
   }
 }
 
+void check_three(std::vector<uint8_t>& rs) {
+  auto n = 0;
+  while (rs[rs.size() - n - 1] == 0x00) {
+    n++;
+  }
+
+  auto needed = 3 - n;
+  while (needed-- > 0) {
+    rs.push_back(0x00);
+  }
+}
+
 std::pair<int, int> day17(line_view file) {
   moves = file;
   rock17 floor{chamber, {0x7F}};
 
-  int n{3};
+  int n{10};
   for (int i = 0; i < n; i++) {
     rock17 r = make_rock(i);
-    auto three{3};
-    while (three-- > 0) {
-      floor.rs.push_back(0x00);
-    }
+    check_three(floor.rs);
     merge(floor, r, 0);
   }
+  print(floor.rs);
+  printf("%ld\n", floor.rs.size() - 4);
 
-  print(floor);
   return {0, 0};
 }
 } // namespace aoc2022