From 1108b8c65bfc61f210548ae7fae0477f0372d173 Mon Sep 17 00:00:00 2001
From: mnerv <24420859+mnerv@users.noreply.github.com>
Date: Mon, 16 Dec 2024 04:03:02 +0100
Subject: [PATCH] aoc24: day07a complete

---
 sol/24/CMakeLists.txt |   2 +-
 sol/24/aoc.cpp        |   2 +-
 sol/24/day07.cpp      | 116 +++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 117 insertions(+), 3 deletions(-)

diff --git a/sol/24/CMakeLists.txt b/sol/24/CMakeLists.txt
index 27fffa7..1263d44 100644
--- a/sol/24/CMakeLists.txt
+++ b/sol/24/CMakeLists.txt
@@ -13,7 +13,7 @@ set(SOURCES
     "day08.cpp"
     "day09.cpp"
     "day10.cpp"
-    "day11.cpp"
+    # "day11.cpp"
 )
 add_library(aoc24 STATIC ${HEADERS} ${SOURCES})
 target_include_directories(aoc24
diff --git a/sol/24/aoc.cpp b/sol/24/aoc.cpp
index ed6931b..17f2a17 100644
--- a/sol/24/aoc.cpp
+++ b/sol/24/aoc.cpp
@@ -28,7 +28,7 @@ auto entry([[maybe_unused]]std::span<char const*> const& args) -> std::expected<
     case 8: return day08(args);
     case 9: return day09(args);
     case 10: return day10(args);
-    case 11: return day11(args);
+    // case 11: return day11(args);
     default:
         return aoc::make_error(fmt::format("day {}", day), std::errc::not_supported);
     }
diff --git a/sol/24/day07.cpp b/sol/24/day07.cpp
index 9435b2c..6c575cd 100644
--- a/sol/24/day07.cpp
+++ b/sol/24/day07.cpp
@@ -1,14 +1,128 @@
+#include <vector>
+#include <ranges>
+#include <numeric>
+
 #include "aoc.hpp"
 #include "aoc/utils.hpp"
 #include "fmt/format.h"
 
+using namespace aoc::types;
+using namespace std::string_view_literals;
+
 namespace rbr {
+enum class op {
+    add,
+    mul,
+};
+
+class expr {
+public:
+    expr(u64 eres, std::vector<u64> const& operands)
+        : m_eres(eres), m_operands(operands) {
+        find_res();
+    }
+
+    auto find_res() -> bool {
+        auto const max = std::pow(2, m_operands.size());
+        for (u32 t = 0; t < max; ++t) {
+            m_ops = t;
+            m_res = 0;
+            compute();
+            if (m_res == m_eres) break;
+        }
+        return m_res == m_eres;
+    }
+    auto compute() -> void {
+        for (usize i = 0; i < m_operands.size(); ++i) {
+            if (i == 0) {
+                m_res = m_operands[0];
+                continue;
+            }
+
+            auto const a = m_res;
+            auto const b = m_operands[i];
+            auto const am = op((m_ops >> (i - 1)) & 0x01);
+            if (am == op::add)
+                m_res = a + b;
+            else
+                m_res = a * b;
+        }
+    }
+    auto res() const -> u64 { return m_eres; }
+    auto eres() const -> u64 { return m_eres; }
+    auto operands() const -> std::vector<u64> const& { return m_operands; }
+    auto ops() const -> u32 const& { return m_ops; }
+    auto valid() const -> bool { return m_res == m_eres; };
+
+    auto str() const -> std::string {
+        using namespace std::string_literals;
+        std::string str{"expr {"};
+        str += " expect: "s + std::to_string(m_eres) + ",";
+        str += " expr: "s;
+        str += std::to_string(m_res) + " = ";
+        for (usize i = 0; i < m_operands.size(); ++i) {
+            auto const& operand = m_operands[i + 0];
+            str += std::to_string(operand);
+            if (i == m_operands.size() - 1) break;
+            str += ((m_ops >> i) & 0x01) == 0x01 ? "+" : "*";
+        }
+        str += " }";
+        return str;
+    }
+
+private:
+    u64 m_eres;
+    std::vector<u64> m_operands;
+    u64              m_res{0x00};
+    u32              m_ops{0x00};
+};
+
+auto str_to_op(std::string const& str) -> expr {
+    auto const splitc = str | std::views::split(": "sv)
+                            | std::views::transform([](auto const& str){
+                                 return std::string(std::begin(str), std::end(str));
+                            })
+                            | std::views::filter([](auto const& str) { return !str.empty(); })
+                            | std::ranges::to<std::vector>();
+
+    u64 const a = std::stoull(splitc[0]);
+    auto const b = splitc[1] | std::views::split(" "sv)
+                             | std::views::transform([](auto const& str){
+                                  return std::string(std::begin(str), std::end(str));
+                             })
+                             | std::views::filter([](auto const& str) { return !str.empty(); })
+                             | std::views::transform([](auto const& str) { return std::stoull(str); })
+                             | std::ranges::to<std::vector>();
+    return {a, b};
+}
 }
 
 auto aoc24::day07([[maybe_unused]]std::span<char const*> const& args) -> std::expected<void, aoc::error> {
-    auto res = aoc::read_text("./dat/24/ex/07.txt");
+    // auto res = aoc::read_text("./dat/24/ex/07.txt");
+    auto res = aoc::read_text("./dat/24/re/07.txt");
     if (!res) return std::unexpected(res.error());
     auto const txt = *res;
 
+    auto exprs = txt | std::views::split("\n"sv)
+                           | std::views::transform([](auto const& str){
+                                return std::string(std::begin(str), std::end(str));
+                           })
+                           | std::views::filter([](auto const& str) { return !str.empty(); })
+                           | std::views::transform(rbr::str_to_op);
+
+    auto const valids = exprs | std::views::filter([](auto const expr) { return expr.valid(); })
+                              | std::views::transform([](auto const& e) { return f64(e.eres()); })
+                              | std::ranges::to<std::vector>();
+
+    auto const sum = std::accumulate(std::begin(valids), std::end(valids), 0.0);
+
+    fmt::print("{}\n", sum);
+
+    // auto const validsex = exprs | std::views::filter([](auto const expr) { return !expr.valid(); })
+    //                             | std::ranges::to<std::vector>();
+    //
+    // for (auto const& exp : validsex) {
+    //     fmt::print("{}\n", exp.str());
+    // }
     return {};
 }