2025D01P1: done

2025/day01.cpp

@@ -1,7 +1,5 @@
 #include <span>
 #include <algorithm>
-#include <cmath>
-#include <numeric>
 #include <ranges>
 #include <string>
 #include <string_view>
@@ -45,7 +43,7 @@ auto trim(std::string s) -> std::string {
 }
 
 // starts at 50
-constexpr auto raw_str = R"(
+[[maybe_unused]]constexpr auto raw_str = R"(
 L68
 L30
 R48
@@ -59,6 +57,7 @@ L82
 )";
 
 enum class rotdir {
+    none,
     L,
     R
 };
@@ -68,14 +67,48 @@ struct rot {
     u32 turns;
 };
 
+auto map_char_to_rotdir(char c) -> rotdir {
+    switch (c) {
+        using enum rotdir;
+        case 'L': return L;
+        case 'R': return R;
+        default: return none;
+    }
+}
+
+auto map_dir_to_i32(i32 value, rotdir dir) -> i32 {
+    switch (dir) {
+        using enum rotdir;
+        case L:  return -value;
+        case R:
+        default: return value;
+    } 
+}
+
 static auto entry([[maybe_unused]]std::span<char const*> const& args) -> void {
-    std::string str{raw_str};
-    str = str | trim;
-    fmt::print("{}\n", str);
+    // std::string str{raw_str};
+    // str = str | trim;
+    auto str = aoc::read_text("./input.txt").value_or("") | trim;
 
     auto rot_vec = str | std::views::split("\n"sv) | std::views::transform([](auto const& str) {
-            return 0;
+            return rot{
+                .dir = map_char_to_rotdir(*std::begin(str)),
+                .turns = u32(std::stoul(std::string{++std::begin(str), std::end(str)}))
+            };
         }) | std::ranges::to<std::vector>();
+
+    i32 start = 50;
+    auto sum = std::ranges::fold_left(rot_vec, 0, [&start](auto a, auto b) {
+            auto c = map_dir_to_i32(b.turns % 100, b.dir);
+
+            start = (100 + start + c) % 100;
+
+            if (start == 0) ++a;
+
+            return a;
+        });
+
+    fmt::print("res: {}\n", sum);
 }
 
 auto main([[maybe_unused]]int argc, [[maybe_unused]]char const* argv[]) -> int {