Dijkstra's algorithm

dijkstra.cpp

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
void split(const std::string &s, char delim, std::vector<std::string> &elems) {
	std::stringstream ss;
	ss.str(s);
	std::string item;
	while (std::getline(ss, item, delim)) {
		elems.push_back(item);
	}
}


std::vector<std::string> split(const std::string &s, char delim) {
	std::vector<std::string> elems;
	split(s, delim, elems);
	return elems;
}

struct edge
{
	unsigned v;
	unsigned length;
};



int main()
{
	std::ifstream input_file("dijkstra.txt");
	std::string line;
	std::multimap<unsigned, edge> map;
	while (std::getline(input_file,line))
	{
		auto words = split(line, '\t');
		unsigned s = std::atoi(words[0].c_str());
		words.erase(words.begin());
		for(auto&& e:words)
		{
			auto p = split(e, ',');
			unsigned v = std::atoi(p[0].c_str());
			unsigned l = std::atoi(p[1].c_str());

			edge edge;
			edge.v = v;
			edge.length = l;
			map.insert({ s,edge });
		}
	}

	unsigned distance[201];
	bool visited[201];
	std::set<unsigned> q;
	for(int i=1;i<=200;i++)
	{
		distance[i] = UINT_MAX;
		q.insert(i);
	}

	distance[1] = 0;

	while (!q.empty())
	{
		auto min=std::min_element(q.cbegin(),q.cend(),[&distance](unsigned a, unsigned b)
		{
			return distance[a] < distance[b];
		});
		auto u = *min;;
		q.erase(min);

		auto it = map.equal_range(u);
		
		for(auto i=it.first;i!=it.second;++i)
		{
			auto p = i->second;
			auto v = p.v;
			auto alt = distance[u] + p.length;
			if(distance[v]>alt)
			{
				distance[v] = alt;
			}
		}
	}
	std::vector<unsigned> o = { 7,37,59,82,99,115,133,165,188,197 };
	for(auto&& x:o)
	{
		std::cout << distance[x] << ',';
	}
	return 0;
}