Cod sursa(job #833297)

Utilizator R.A.RFMI Romila Remus Arthur R.A.R Data 12 decembrie 2012 11:14:26
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.16 kb
#include <fstream>
#include <vector>
#define LS (node<<1)
#define RS ((node<<1)+1)
#define  INF (1<<30)
#define IMAX (1<<17)
#define NMAX 50004
#define LIM (1<<15)
#define cont ++poz == LIM ? in.read(T,LIM),poz = 0 : 0
 
using namespace std;
 
ifstream in("dijkstra.in");
ofstream out("dijkstra.out");
 
/**************************/
char T[LIM+4];
int poz;
void Citeste(int &n)
{
    if(T[0] == '\0')in.read(T,LIM);
    else for(;T[poz]<'0'||T[poz]>'9';cont);
    for(n = 0;T[poz]>='0'&&T[poz]<='9';n = n*10+T[poz]-'0',cont);
}
/*************************/
 
int N,M,D[NMAX],Dist[NMAX];
 
vector<pair<int,int> > V[NMAX];
 
int AInt[IMAX];
 
void Refresh(int node,int start,int final)
{
    if(start == final)
        AInt[node] = start;
    else
    {
        int med = (start + final) / 2;
        Refresh(LS,start,med);
        Refresh(RS,med+1,final);
        if(D[AInt[LS]] < D[AInt[RS]])
             AInt[node] = AInt[LS];
        else AInt[node] = AInt[RS];
    }
}
 
void Update(int node,int start,int final,int pos)
{
    if(start == final);
    else
    {
        int med = (start + final) / 2;
        if(pos<=med)
             Update(LS,start,med,pos);
        else Update(RS,med+1,final,pos);
         
        if(D[AInt[LS]] < D[AInt[RS]])
             AInt[node] = AInt[LS];
        else AInt[node] = AInt[RS];
    }
}
int main ()
{
    int i,x,y,c;
    int Empty = 1;
    Citeste(N),Citeste(M);
    while(M--)
    {
        Citeste(x),Citeste(y),Citeste(c);
        V[x].push_back(make_pair(y,c));
    //  V[y].push_back(make_pair(x,c));
    }
    for(i=2;i<=N;i++)
        D[i] = Dist[i] = INF;
     
    Refresh(1,1,N);
     
    while(Empty)
    {
        x = AInt[1];//TOP
        //POP
        if(D[x] == INF)
            Empty = 1;
        D[x] = INF;
        Update(1,1,N,x);
        for(i=0;i<V[x].size();i++)
        {
            y = V[x][i].first;
            c = V[x][i].second;
            if(Dist[y] > Dist[x]+c)
                D[y] = Dist[y] = Dist[x]+c,Update(1,1,N,y),Empty ++;
        }
        Empty--;
    }
    for(i=2;i<=N;i++)
        out<<(Dist[i]!= INF ? Dist[i] : 0)<<' ';
}