Cod sursa(job #2540503)

Utilizator CandyBucherGaube Robert Gabriel CandyBucher Data 7 februarie 2020 11:46:15
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.82 kb
#include<iostream>
#include<vector>
#include<fstream>
#include<bitset>
#define inf 100000000
using namespace std;
int n;
int heap[1000],k=0,d[1000];

vector <pair<int,int> > v[1000];
bitset <1000> viz;

void citire();
void dijkstra();
void afisare();

int main(){
    citire();
    dijkstra();
    afisare();
}

void afisare(){
    int i;
    ofstream o("dijkstra.out");
    for(i=2;i<=n;i++) o<<d[i]<<" ";
    o.close();
}
void initializare(){
    int i;
    for(i=2;i<=n;i++)
        d[i]=inf;
    viz[1]=1; heap[++k]=1;
}
void swap(int x,int y){
    int a;
    a=heap[x];
    heap[x]=heap[y];
    heap[y]=a;
}
void downheap(){
    swap(1,k); k--;
    int index=1,f;
    while(index<=k){
        f=index<<1;
        if(f<=k){
            if(d[heap[f+1]]<d[heap[f]])
                if(f+1<=k) f++;
                else return;
        }
        else return;
        if(d[heap[f]]<d[heap[index]]){
            swap(f,index);
            index=f;
        }
        else return;
    }
}
void upheap(int x){
    heap[++k]=x;
    int index=k,t;
    while(index>1){
        t=index>>1;
        if(d[heap[t]]>d[heap[index]]){
            swap(t,index);
            index=t;
        }
        else return;
    }
}
void dijkstra(){
    initializare();
    int nod,i,nv,cv;
    while(k){
        nod=heap[1];
        viz[nod]=1;
        downheap();
        for(i=0;i<v[nod].size();i++){
            nv=v[nod][i].first;
            cv=v[nod][i].second;
            if(d[nod]+cv<d[nv]){
                d[nv]=d[nod]+cv;
                if(!viz[nv]) upheap(nv);
            }
        }
    }
}
void citire(){
    ifstream f("dijkstra.in");
    int m,x,y,c,i; f>>n>>m;
    for(i=1;i<=m;i++){
        f>>x>>y>>c;
        v[x].push_back(make_pair(y,c));
    }
    f.close();
}