Cod sursa(job #2613983)

Utilizator raresAlex95Rares Stan raresAlex95 Data 10 mai 2020 23:29:39
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.58 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#include <queue>

using namespace std;

ifstream in("dijkstra.in");
ofstream out("dijkstra.out");

struct nodeCost
{
  int node, cost;
};

struct classcomp
{
  bool operator()(nodeCost a, nodeCost b) const
  {
    return a.cost < b.cost;
  }
};

vector<int> calculateCosts(vector<vector<int>> &graph)
{
  set<nodeCost, classcomp> costs;
  vector<int> finalCosts(graph.size(), INT_MAX);

  costs.insert({0, 0});
  for (int i = 1; i < graph.size(); i++)
  {
    costs.insert({i, INT_MAX});
  }

  while (costs.size() > 0)
  {
    auto first = *(costs.begin());
    if (first.cost == INT_MAX)
    {
      break;
    }

    finalCosts[first.node] = first.cost;

    for (int i = 0; i < graph.size(); i++)
    {
      int drum = graph[first.node][i], lungNou = first.cost + graph[first.node][i];
      if (drum != INT_MAX && finalCosts[i] > lungNou)
      {
        costs.erase({i, finalCosts[i]});
        costs.insert({i, lungNou});
        finalCosts[i] = lungNou;
      }
    }

    costs.erase(first);
  }

  return finalCosts;
}

int main()
{
  int n, m, a, b, v;

  in >> n >> m;

  vector<vector<int>> graph(n);

  for (int i = 0; i < n; i++)
  {
    vector<int> tmp(n, INT_MAX);
    graph[i] = tmp;
  }

  for (int i = 0; i < m; i++)
  {
    in >> a >> b >> v;
    graph[a - 1][b - 1] = v;
    graph[b - 1][a - 1] = v;
  }

  auto aa = calculateCosts(graph);

  for (int i = 1; i < aa.size(); i++)
  {
    out << aa[i] << ' ';
  }

  return 0;
}