Cod sursa(job #2547070)

Utilizator RedPipperNastasa Stefan-Alexandru RedPipper Data 14 februarie 2020 22:16:27
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.83 kb
#include <bits/stdc++.h>
#define pii pair<int,int>
#define make_pii(a,b) make_pair(a,b)
#define INF -1

using namespace std;
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");
int n,m;
const int lmt = 5e4+1;
int dist[lmt]={INF};
bool  viz[lmt];
vector<pii> aList[lmt];
priority_queue<pii, vector<pii>, greater<pii> > pq;

void citire()
{
    fin>>n>>m;
    for(int i=1;i<=m;++i)
    {
        int x,y,p;
        fin>>x>>y>>p;
        pii a = make_pii(y,p);
        aList[x].push_back(a);
    }
    //first ii nodul, second ii costul
}



void dijkstra(int nod)
{
    //first ii nodul curent si second ii distanta de la el la nod
    pii strtNod = make_pii(nod,0);
    dist[nod] = 0;
    viz[strtNod.first] = 1;
    pq.push(strtNod);
    while(!pq.empty())
    {
        pii crnt = pq.top();
        pq.pop();
        viz[crnt.first]=1;
        if(dist[crnt.first] < crnt.second)
            continue;

        vector<pii>::iterator i;
        for(i = aList[crnt.first].begin();i!=aList[crnt.first].end();++i)
        {
            pii nd = *i;
            if(viz[nd.first])continue;

            int newDistance = dist[crnt.first] + nd.second;

            if(dist[nd.first] == INF)
            {
                dist[nd.first] = newDistance;
                pii toAdd = make_pii(nd.first,dist[nd.first]);
                pq.push(toAdd);
            }
            else if(dist[nd.first]>newDistance)
            {
                dist[nd.first] = newDistance;
                pii toAdd = make_pii(nd.first,dist[nd.first]);
                pq.push(toAdd);
            }

        }

    }

}

int main()
{
    citire();
    for(int i=1;i<=n;++i)
        dist[i]=INF;
    dijkstra(1);
    for(int i=2;i<=n;++i)
        fout<<(dist[i] == INF ? 0 : dist[i])<<' ';


    return 0;
}