#include <iostream>
#include <vector>
#include <unordered_map>
 
std::pair<int, int> find_range_with_sum(std::vector<int> const& numbers, int k) {
	std::unordered_map<int, int> sum_map;
	sum_map.emplace(0, 0);
	int sum = 0;
	for (int i = 0; i < numbers.size(); i++) {
		sum += numbers[i];
		auto it = sum_map.find(sum - k);
		if (it != sum_map.end()) {
			return std::make_pair(it->second, i);
		}
		sum_map.emplace(sum, i+1);
	}
	return std::make_pair(-1, -1);
}
 
int main() {
	std::vector<int> numbers = {-1, 5, -3, 5, 1, 2, -4, 6, -2};
	auto range = find_range_with_sum(numbers, 1);
 
	//output
	std::cout << range.first+1 << ". to " << range.second+1 << "." << std::endl;
	return 0;
}

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