Cod sursa(job #2845555)

Utilizator MenelausSontea Vladimir Menelaus Data 7 februarie 2022 22:49:46
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.47 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <set>

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

const int N=50000;
const int M=250000;
const int INF=2000000000;

struct muchie
{
    int from;
    int to;
    int cost;
};

std::vector<int> v[N+1];
muchie edge[M+1];
int dist[N+1];
bool marked[N+1];

bool compare(int a, int b)
{
    return dist[a]<dist[b];
}

std::set<int, decltype(&compare)> q(&compare);

void Dijkstra(int start)
{
    q.insert(1);
    dist[1]=0;

    while(!q.empty())
    {
        int curr=*q.begin();
        q.erase(q.begin());

        for(int l : v[curr])
        {
            int to = edge[l].from + edge[l].to - curr;

            if(!marked[to])
            {
                if(dist[curr] + edge[l].cost < dist[to])
                {
                    if(q.find(to)!=q.end())
                    {
                        q.erase(to);
                    }
                    dist[to]=dist[curr]+edge[l].cost;
                    q.insert(to);
                }
            }
        }

        marked[curr]=1;
    }
}

int n, m;

int main()
{
    in>>n>>m;
    for(int i=1; i<=m; i++)
    {
        in>>edge[i].from>>edge[i].to>>edge[i].cost;
        v[edge[i].from].push_back(i);
    }

    for(int i=1; i<=n; i++)
    {
        dist[i]=INF;
    }

    Dijkstra(1);

    for(int i=2; i<=n; i++)
    {
        out<<dist[i]<<" ";
    }
}