Pagini recente » Cod sursa (job #1906085) | Cod sursa (job #2761028) | Cod sursa (job #1591558) | Cod sursa (job #1976020) | Cod sursa (job #2638785)
#include <fstream>
#include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
#include <queue>
#include <cmath>
#include <string>
#include <set>
using namespace std;
ifstream in("dijkstra.in");
ofstream out("dijkstra.out");
// DIJSKTRA with MIN-HEAP using SET
#define INF 20000000
const int NMAX = 50015;
vector<pair<int, int>> adjList[NMAX];// vector <adjNode,edgeCost>
int dist[NMAX];
int n, m;
void read()
{
in >> n >> m;
for (int i = 0; i < m; i++)
{
int x, y, c;
in >> x >> y >> c;
adjList[x].push_back(make_pair(y, c));
}
}
void Dijsktra(int startNode)
{
dist[startNode] = 0;
set<pair<int, int>> heap;
heap.insert(make_pair(startNode, 0)); // <node,cost>
while (!heap.empty())
{
int node = heap.begin()->first;
heap.erase(heap.begin());
for (const auto& edge : adjList[node])
{
int nextNode = edge.first;
int cost = edge.second;
if (dist[nextNode] > dist[node] + cost)
{
if (dist[nextNode] != INF) //already exists(visited)
{
heap.erase(heap.find({ nextNode, dist[nextNode] }));
// we remove the element
// in order to update it
}
dist[nextNode] = dist[node] + cost;
heap.insert({ nextNode, dist[nextNode] });
}
}
}
}
void print()
{
for (int i = 2; i <= n; i++)
{
if (dist[i] == INF)//unvisited
dist[i] = 0;
out << dist[i] << ' ';
}
}
int main()
{
read();
for (int i = 0; i <= n + 1; i++)
dist[i] = INF;
Dijsktra(1);
print();
}