2015 day23

1 files changed, 94 insertions, 1 deletions

diff --git a/src/2015/day23/aoc.cpp b/src/2015/day23/aoc.cpp
index 9cb0cef..fd64a06 100644
--- a/src/2015/day23/aoc.cpp
+++ b/src/2015/day23/aoc.cpp
@@ -1,11 +1,104 @@
 #include "aoc.h"
 #include <string.h>
 #include <vector>
+#include <functional>
 
 namespace aoc2015 {
+static int registers[2] = {0};
+
+void execute(size_t i, const std::vector<line_view>& is);
+void hlf(size_t i, const std::vector<line_view>& is, const char *p) {
+  int x = *p == 'a' ? 0 : 1;
+  registers[x] /= 2;
+  execute(i+1, is);
+}
+
+void tpl(size_t i, const std::vector<line_view>& is, const char *p) {
+  int x = *p == 'a' ? 0 : 1;
+  registers[x] *= 3;
+  execute(i+1, is);
+}
+
+void inc(size_t i, const std::vector<line_view>& is, const char *p) {
+  int x = *p == 'a' ? 0 : 1;
+  registers[x] += 1;
+  execute(i+1, is);
+}
+
+static int get_number(const char *p) {
+  int sign = *p == '+' ? 1 : -1;
+  p++;
+  int d{0};
+  while(*p <= '9' && *p >= '0') {
+    d = 10 * d + *p - '0';
+    p++;
+  }
+  d *= sign;
+  return d;
+}
+
+void jmp(size_t i, const std::vector<line_view>& is, const char *p) {
+  int d = get_number(p);
+  execute(i+d, is);
+}
+
+void jie(size_t i, const std::vector<line_view>& is, const char *p) {
+  int x = *p == 'a' ? 0 : 1;
+  p += 3;
+  int d = registers[x] % 2 == 0 ? get_number(p) : 1;
+  execute(i+d, is);
+}
+
+void jio(size_t i, const std::vector<line_view>& is, const char *p) {
+  int x = *p == 'a' ? 0 : 1;
+  p += 3;
+  int d = registers[x] == 1 ? get_number(p) : 1;
+  execute(i+d, is);
+}
+
+void execute(size_t i, const std::vector<line_view>& is) {
+  if (i >= is.size()) {
+    return;
+  }
+  line_view cmd = is[i];
+  const char* p = cmd.line;
+  struct {
+    const char* ins;
+    std::function<void(size_t, const std::vector<line_view>&, const char*)> f;
+  } cmds[] = {
+    {"hlf", hlf},
+    {"tpl", tpl},
+    {"inc", inc},
+    {"jmp", jmp},
+    {"jie", jie},
+    {"jio", jio},
+  };
+
+  for(auto& c : cmds) {
+    if (strncmp(p, c.ins, 3) == 0) {
+      c.f(i, is, p+4);
+      break;
+    }
+  }
+
+}
 
 std::pair<int, int> day23(line_view file) {
-  return {0, 0};
+  std::vector<line_view> is;
+  per_line(file, [&is](line_view lv){
+      is.push_back(lv);
+      return true;
+  });
+
+  execute(0, is);
+  int a1 = registers[1];
+
+  registers[0] = 1;
+  registers[1] = 0;
+
+  execute(0, is);
+  int a2 = registers[1];
+  return {a1, a2};
 }
 
 }