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Cod sursa(job #611157)
#include<fstream>
using namespace std;
const int inf = 1<<30;
#define MAX 50000
typedef struct graf
{
int nod,et;
graf* next;
}graf;
int N,M,d[MAX];
graf* a[MAX];
int minHeap[MAX],heapSize,poz[MAX];
bool T[MAX];
void shiftDown(int i);
void adaug(int x,int y,int et)
{
graf* aux = new graf();
aux->et=et;
aux->nod = y;
aux->next = a[x];
a[x] = aux;
}
void shiftUp(int i)
{
int parent,aux;
if(i!=0)
{
parent = (i-1)/2;
if(d[minHeap[parent]] > d[minHeap[i]])
{
poz[minHeap[i]] = parent;
poz[minHeap[parent]] = i;
aux = minHeap[i];
minHeap[i] = minHeap[parent];
minHeap[parent] = aux;
shiftUp(parent);
}
}
else
shiftDown(0);
}
void insertHeap(int i)
{
minHeap[heapSize] = i;
poz[i] = heapSize;
shiftUp(heapSize++);
}
void shiftDown(int i)
{
int aux;
int child = i*2+1;
if(child<heapSize)
{
if(d[minHeap[i]] > d[minHeap[child]])
{
poz[minHeap[i]] = child;
poz[minHeap[child]] = i;
aux = minHeap[i];
minHeap[i] = minHeap[child];
minHeap[child] = aux;
shiftDown(child);
}
else
{
child++;
if(child<heapSize && d[minHeap[i]] > d[minHeap[child]])
{
poz[minHeap[i]] = child;
poz[minHeap[child]] = i;
aux = minHeap[i];
minHeap[i] = minHeap[child];
minHeap[child] = aux;
shiftDown(child);
}
}
}
}
void removeHeap()
{
minHeap[0] = minHeap[--heapSize];
shiftDown(0);
}
void citire()
{
ifstream f("dijkstra.in");
f>>N>>M;
int x,y,z;
for(int i=0;i<M;i++)
{
f>>x>>y>>z;
adaug(x-1,y-1,z);
}
f.close();
for(int i=1;i<N;i++)
{
T[i] = false;
d[i] = inf;
}
graf* aux = new graf();
aux = a[0];
while(aux)
{
d[aux->nod] = aux->et;
aux = aux->next;
}
for(int i=1;i<N;i++)
insertHeap(i);
T[0] = true;
};
void solve()
{
int xp;
while(heapSize)
{
xp = minHeap[0];
T[xp] = true;
removeHeap();
graf* aux = new graf();
aux = a[xp];
while(aux)
{
if(!T[aux->nod] && d[aux->nod]>d[xp]+aux->et)
{
d[aux->nod] = d[xp]+aux->et;
shiftUp(poz[aux->nod]);
}
aux= aux->next;
}
}
ofstream g("dijkstra.out");
for(int i=1;i<N;i++)
if(d[i]!=inf)
g<<d[i]<<" ";
else
g<<"0 ";
g.close();
}
int main()
{
citire();
solve();
return 0;
}