Finally working for one case.

CMakeLists.txt

@@ -7,8 +7,7 @@ find_package(PkgConfig REQUIRED)
 
 pkg_check_modules(Jemalloc REQUIRED jemalloc)
 
-set(LINKER_OPTIONS
-    PRIVATE -Wl,--sort-common,--as-needed,--gc-sections,--strip-all)
+set(LINKER_OPTIONS -Wl,--sort-common,--as-needed,--gc-sections,--strip-all)
 
 set(COMPILE_FLAGS
     -pipe
@@ -52,7 +51,9 @@ set_target_properties(AdventOfCode2023 pb_1 PROPERTIES
                       INTERPROCEDURAL_OPTIMIZATION ON
                       UNITY_BUILD ON
 )
+target_compile_definitions(AdventOfCode2023 PUBLIC $<$<AND:$<CONFIG:Debug>,$<STREQUAL:$<CXX_COMPILER_ID>,GNU>>:_GLIBCXX_DEBUG>)
+target_compile_definitions(pb_1 PUBLIC $<$<AND:$<CONFIG:Debug>,$<STREQUAL:$<CXX_COMPILER_ID>,GNU>>:_GLIBCXX_DEBUG>)
 target_compile_options(AdventOfCode2023 PUBLIC ${COMPILE_OPTIONS})
 target_link_options(AdventOfCode2023 PUBLIC ${LINKER_OPTIONS})
 target_link_libraries(AdventOfCode2023 PUBLIC pb_1 ${Jemalloc_LIBRARIES})
-target_link_libraries(pb_1 ${Jemalloc_LIBRARIES})
+target_link_libraries(pb_1 PUBLIC ${Jemalloc_LIBRARIES})

inputs/pb1_p2_sample.txt

@@ -1,6 +1,6 @@
+abcone2threexyz
 two1nine
 eightwothree
-abcone2threexyz
 xtwone3four
 4nineeightseven2
 zoneight234

pb_1/problem_1.cpp

@@ -4,6 +4,10 @@
 
 #include "problem_1.hpp"
 #include <array>
+#include <string>
+#include <string_view>
+#include <optional>
+#include <unordered_set>
 #include <vector>
 #include <fstream>
 #include <iostream>
@@ -26,6 +30,18 @@ namespace pb1 {
             "nine"sv,
     };
 
+    const std::unordered_set numbersSet{
+            "one"sv,
+            "two"sv,
+            "three"sv,
+            "four"sv,
+            "five"sv,
+            "six"sv,
+            "seven"sv,
+            "eight"sv,
+            "nine"sv,
+    };
+
     std::optional<std::ifstream> read_file(const fs::path &problemFile) noexcept {
         std::ifstream file(problemFile);
         if (!file.is_open()) {
@@ -76,10 +92,52 @@ namespace pb1 {
     }
 
     void part2(const std::string_view &toSearch, std::vector<std::string> &splittedLine, std::size_t &result) noexcept {
-        std::string line_with_numbers;
+        std::string line_with_numbers, word;
         line_with_numbers.reserve(toSearch.size());
+        word.reserve(sizeof("seven") - 1);
         for (int i = 0; i < toSearch.size(); ++i) {
-
+            const int second_letter = i + 1, third = i + 2, fourth = i + 3, fifth = i + 4, sixth = i + 5;
+            switch (toSearch[i]) {
+                case 'o': {
+                    if (second_letter >= toSearch.size() or third >= toSearch.size()) {
+                        line_with_numbers.append(toSearch.substr(i));
+                        continue;
+                    }
+                    word.append(toSearch.substr(i, digitLetters[0].size()));
+                    if (!numbersSet.contains(word)) {
+                        const auto pos = word.find_first_of(digits);
+                        if (pos != std::string::npos) {
+                            line_with_numbers.push_back(word[pos]);
+                        }
+                        if (word[1] == 'n') {
+                            ++i;
+                        }
+                    } else {
+                        line_with_numbers.push_back('1');
+                        ++i;
+                    }
+                    word.clear();
+                }
+                    break;
+                case 't':
+                    break;
+                case 'f':
+                    break;
+                case 's':
+                    break;
+                case 'e':
+                    break;
+                case 'n':
+                    break;
+                default:
+                    if ((toSearch[i] - '0') < 10) {
+                        line_with_numbers.push_back(toSearch[i]);
+                    }
+                    continue;
+            }
+        }
+        if (!line_with_numbers.empty()) {
+            result += (line_with_numbers.front() - '0') * 10 + (line_with_numbers.back() - '0');
         }
     }