1 files changed, 107 insertions, 1 deletions
diff --git a/src/2019/day3/aoc.h b/src/2019/day3/aoc.h
index 959d6d8..48b6812 100644
--- a/src/2019/day3/aoc.h
+++ b/src/2019/day3/aoc.h
@@ -1,6 +1,112 @@
 #pragma once
 #include "common.h"
+#include <algorithm>
+#include <functional>
+#include <vector>
 
 namespace aoc2019 {
 
-}
+struct day3point {
+  int x;
+  int y;
+
+  int distance() const noexcept { return std::abs(x) + std::abs(y); }
+  bool operator<(const day3point& other) const noexcept { return distance() < other.distance(); }
+};
+
+struct wire {
+  struct part {
+    enum dir_t {
+      up,
+      right,
+      down,
+      left,
+    } dir;
+    int distance;
+  };
+
+  day3point mov(day3point p, part pa) const noexcept {
+    auto addy = [&p](int d) -> day3point { return {p.x, p.y + d}; };
+    auto addx = [&p](int d) -> day3point { return {p.x + d, p.y}; };
+    auto suby = [&p](int d) -> day3point { return {p.x, p.y - d}; };
+    auto subx = [&p](int d) -> day3point { return {p.x - d, p.y}; };
+    std::function<day3point(int)> fs[] = {addy, addx, suby, subx};
+    return fs[int(pa.dir)](pa.distance);
+  }
+
+  struct line {
+    day3point a;
+    day3point b;
+  };
+
+  std::vector<line> psh;
+  std::vector<line> psv;
+
+  void sort() {
+    std::sort(psh.begin(), psh.end(),
+              [](const line& l1, const line& l2) { return std::abs(l1.a.y) < std::abs(l2.a.y); });
+    std::sort(psv.begin(), psv.end(),
+              [](const line& l1, const line& l2) { return std::abs(l1.a.x) < std::abs(l2.a.x); });
+  }
+
+  void get_part(const char** pp, int* d) {
+    *d = 0;
+    const char* p = *pp + 1;
+    while (*p >= '0' && *p <= '9') {
+      *d = *d * 10 + *p - '0';
+      p++;
+    }
+    *pp = p;
+  }
+
+  void largest(day3point* cp, day3point* mp) {
+    if (std::abs(cp->x) > std::abs(mp->x)) {
+      mp->x = cp->x;
+    }
+    if (std::abs(cp->y) > std::abs(mp->y)) {
+      mp->y = cp->y;
+    }
+  }
+
+  void parse(line_view lv, day3point* cp, day3point* mp) {
+    part p;
+    const char* p1 = lv.line;
+    auto make_part = [&p, &p1, cp, mp, this](part::dir_t d) {
+      p.dir = d;
+      get_part(&p1, &p.distance);
+      day3point a = *cp;
+      *cp = mov(*cp, p);
+      // printf("%d, %d\n", cp->x, cp->y);
+      largest(cp, mp);
+      if (d == part::right || d == part::left) {
+        psh.push_back({a, *cp});
+      }
+      if (d == part::up || d == part::down) {
+        psv.push_back({a, *cp});
+      }
+    };
+    while (p1 < lv.line + lv.length) {
+      switch (*p1) {
+      case 'R':
+        make_part(part::right);
+        break;
+      case 'L':
+        make_part(part::left);
+        break;
+      case 'U':
+        make_part(part::up);
+        break;
+      case 'D':
+        make_part(part::down);
+        break;
+      default:
+        break;
+      }
+      p1++;
+    }
+  }
+};
+
+int day3(line_view);
+
+} // namespace aoc2019