#include <vector>
#include <iostream>
 
std::vector<std::pair<int, int>> rle(const std::vector<int>& in)
{
	std::vector<std::pair<int, int>> out;
	for (int i: in)
	{
			 if (out.empty() || out.back().first != i)
			 {
					 out.emplace_back(std::make_pair(i, 1));
			 }
			 else
			 {
					 ++out.back().second;
			 }
	}
	return out;
}
 
int main()
{
	auto out = rle({1,1,1,3,4,2,2,2,2,51});
	for (const auto& pair : out)
	{
		std::cout << pair.first << ": " << pair.second << ", ";
	}
	std::cout << std::endl;
}
 

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