Cod sursa(job #1587927)

Utilizator metrix007Lungu Ioan Adrian metrix007 Data 2 februarie 2016 17:50:56
Problema Algoritmul lui Dijkstra Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 2.83 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define NMAX 50002
#define INF 999999999
using namespace std;

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

struct graf
{
    int nod,c;
}pc,cod;

int n,m,grad,x,y,cost;
vector<graf> a[NMAX];
graf heap[NMAX];
int d[NMAX];

struct comp{
    bool operator() (graf a, graf b)
    {
        if(a.c < b.c)
            return true;
        return false;
    }
};

void sus(int x)
{
    while(heap[x/2].c>heap[x].c && x>1)
    {
        swap(heap[x/2],heap[x]);
        x = x/2;
    }
}

void jos(int x)
{
    while((heap[x].c > heap[x*2+1].c && x*2+1<=grad) || (heap[x].c>heap[x*2].c && x*2<=grad))
    {

        if(heap[x*2].c > heap[x*2+1].c && x*2+1<=grad)
        {
            swap(heap[x],heap[x*2+1]);
           // x = x*2+1;
        }
        else if(x*2<=grad)
        {
            swap(heap[x],heap[x*2]);
            //x = x*2;
        }
    }
}


graf Min()
{
    graf M = heap[1];
    if(grad>0)
        heap[1] = heap[grad--];
    jos(1);
    return M;
}

void Insert(graf a)
{
    heap[++grad] = a;
    sus(grad);
}

//void dijkstra()
//{
//
//    for(int i=2;i<=n;i++)
//        d[i] = INF;
//    pc.c = 0; pc.nod = 1;
//    Insert(pc);
//   coada.push(pc);
//    while(grad!=0)
//        while(!coada.empty())
//    {
//
//        pc = Min();
//         pc = coada.top(); coada.pop();
//
//        for(int i=0;i<a[pc.nod].size();i++)
//        {
//           cout << pc.c;
//            if(d[a[pc.nod][i].nod] > pc.c + a[pc.nod][i].c)
//            {
//
//                d[a[pc.nod][i].nod] = pc.c + a[pc.nod][i].c;
//                cod.c = d[a[pc.nod][i].nod];
//                cod.nod = a[pc.nod][i].nod;
//                Insert(cod);
//                coada.push(cod);
//            }
//        }
//    }
//}

void dijkstra1()
{
       for(int i=2;i<=n;i++)
       d[i] = INF;
    priority_queue<graf, vector<graf> ,comp> T;
    int nods,costs,di,val,x;
    pc.c = 0;
    pc.nod =1;
    T.push(pc);
    while(!T.empty())
    {
        val = T.top().c;
        x = T.top().nod;
        T.pop();
        di = a[x].size();
        for(int i=0;i<di;++i)
        {
            if(d[a[x][i].nod]> val + a[x][i].c)
            {
                d[a[x][i].nod]= val + a[x][i].c;
                pc.c = d[a[x][i].nod];
                pc.nod = a[x][i].nod;
                T.push(pc);
            }
        }
    }
}

int main()
{
    in >> n >> m;
    for(int i=1;i<=m;i++)
    {
        in >> x >> y >> cost;
        pc.nod = y;
        pc.c = cost;
        a[x].push_back(pc);

    }
    dijkstra1();
    for(int i=2;i<=n;i++)
        if(d[i]!=INF)
            out << d[i] << " ";
        else
            out << 0 << " ";

    return 0;
}