implementation

day01cpp/main.cpp

-int main() {}
+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <ranges>
+#include <set>
+#include <string>
+
+void part_a() {
+    std::ifstream data("data.txt");
+    std::string   line;
+    int           sum = 0;
+
+    while (std::getline(data, line)) {
+        int a = *std::ranges::find_if(line.begin(), line.end(), [](char c) {
+            return std::isdigit(c);
+        }) - '0';
+        int b = *std::ranges::find_if(line.rbegin(), line.rend(), [](char c) {
+            return std::isdigit(c);
+        }) - '0';
+        sum += a * 10 + b;
+    }
+
+    std::cout << sum << std::endl;
+}
+
+void part_b() {
+    std::ifstream data("data.txt");
+
+    constexpr std::array<std::string_view, 9> numbers
+        = { "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
+
+    std::string line;
+    uint32_t    sum = 0;
+
+    while (std::getline(data, line)) {
+        std::pair num_a { 0, line.size() };
+        for (size_t index = 0; index < numbers.size(); ++index) {
+            auto offset = std::min(line.find(numbers[index]), line.find(std::to_string(index + 1)));
+            if (offset != line.npos && offset < num_a.second) {
+                num_a.first  = index + 1;
+                num_a.second = offset;
+            }
+        }
+
+        std::pair num_b { 0, -1 };
+        for (size_t index = 0; index < numbers.size(); ++index) {
+            std::set found = { line.rfind(numbers[index]), line.rfind(std::to_string(index + 1)) };
+            found.erase(line.npos);
+
+            if (!found.empty()) {
+                auto offset = std::ranges::max(found);
+                if (static_cast<int>(offset) > num_b.second) {
+                    num_b.first  = index + 1;
+                    num_b.second = offset;
+                }
+            }
+        }
+
+        sum += num_a.first * 10 + num_b.first;
+    }
+
+    std::cout << sum << std::endl;
+}
+
+int main() {
+    part_a();
+    part_b();
+}