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const char * singleC = strstr(src, "//");
const char * multiC = strstr(src, "/*");
const char * eol = strstr(src, "\n");
 
const char * min = nullptr;
if (singleC) min = singleC;
if (multiC && (!min || (multiC < min))) min = multiC;
if (eol && (!min || (eol < min))) min = eol;
 
if (!min) return;
 
if (min == singleC) {
 ...
}
 
if (min == multiC) {
 ...
}
 
if (min == eol) {
 ...
}

using TPair = std::pair<size_t, size_t>;    // position + index
 
TPair FindClosestMatch( std::string_view src, const std::vector<std::string_view> & matches )
{
    for (size_t pos = 0; pos < src.size(); ++pos)
        for (size_t idx = 0; idx < matches.size(); ++idx)
            if (src.compare(pos, src.size() - pos, matches[idx]) == 0)
                return TPair(pos, idx);
 
    return TPair(std::string_view::npos, std::string_view::npos);
}

#include <iostream>
#include <algorithm>
#include <string>
#include <string_view>
#include <utility>
#include <ranges>
#include <vector>
#include <optional>
#include <format>
 
using ReturnType = std::optional<std::pair<int, int>>;
 
template<class Container, class Needles>
ReturnType foo(Container &&container,  Needles &&needles){
    
    if(!std::ranges::range<Container> || !std::ranges::range<Needles>)
       return std::nullopt;
    
    int end{-1};
    int start = std::distance(std::begin(container), std::end(container));
    
    for(const auto &needle : needles){
        if(auto res = std::ranges::search(container, needle); !res.empty()) {
            const auto first = std::distance(std::begin(container), std::begin(res));
            if(first < start){
                start = first;
                end = std::distance(std::begin(container), std::end(res));;
            }
        }
    }
    if(end > 0)
        return ReturnType{std::pair(start, end)};
    else 
        return std::nullopt;
}
 
 
int main()
{
    auto print = [](std::string_view title, const ReturnType &res){
        std::cout << std::format("{}, from {} to {}\n", title, res.value().first, res.value().second);
    };
   
    //const char* charStr = "somesex text";
    //std::string testString(charStr);
    std::string testString = "somesex text";
    std::vector<std::string> needle = {"ex", "tex", "al"};
    if(auto res = foo(testString, needle))
       print("string", res);
    
    std::string_view testStringView = testString;
    if(auto res = foo(testStringView, needle))
       print("string view", res);
       
    if(auto res = foo("literal", needle))
       print("literal", res);
       
    std::vector<int> intVector = {1,2,3};
    std::vector<std::vector<int>>intNeedles = {{3},{2}}; // кхе кхе :)
    if(auto res = foo(intVector, intNeedles))
       print("int vector", res); 
       
    int intArr1[] = {3,2,1};
    if(auto res = foo(intArr1, intNeedles))
       print("int c array", res);
    
    return 0;
}

using ReturnType = std::optional<std::pair<int, int>>;
 
template<std::ranges::forward_range Container, std::ranges::forward_range Needles, class Pred = std::ranges::equal_to>
ReturnType foo(Container &&container,  Needles &&needles, Pred pred = {}){
    
    //?
    //if(!std::ranges::range<Container> || !std::ranges::range<Needles>)
    //   return std::nullopt;
    
    int end{-1};
    int start = std::distance(std::begin(container), std::end(container));
        
    for(const auto &needle : needles){
        if (auto res = std::ranges::search(container, needle, pred); !res.empty()) {
            const auto first = std::distance(std::begin(container), std::begin(res));
            if(first < start){
                start = first;
                end=std::distance(std::begin(container), std::end(res));
            }
        }
    }
    if(end>0)
        return ReturnType{std::pair(start, end)};
    else 
        return std::nullopt;
}
 
...
 
    std::string testString = "someSEX  text";
    std::vector<std::string> needle = {"ex", "tex", "al"};
    auto pred=[](auto a, auto b){
        return std::tolower(a) == std::tolower(b);
    };
    if(auto res = foo(testString, needle, pred))
       print("string", res);