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Cod sursa(job #544437)
#include <vector>
#include <fstream>
#include <cstdlib>
#define N_MAX 50011
#define oo 1<<20
#define pr pair< int, int >
#define mkpr make_pair< int, int >
using namespace std;
int N;
vector< pr > G[N_MAX];
vector< pr >::const_iterator it, iend;
bool isIn[N_MAX];
int H[N_MAX], P[N_MAX], d[N_MAX];
inline void _swap( int& x, int& y ) { int aux=x; x=y; y=aux; }
inline int _min( int x, int y ) { return ( x <= y ? x : y ); }
inline int _max( int x, int y ) { return ( x >= y ? x : y ); }
void DownHeap( int k )
{
for( int son=2*k; son <= N; son*=2 )
{
if( son < N && d[H[son]] > d[H[son+1]] )
++son;
if( H[k] <= H[son] )
return;
_swap( H[k], H[son] );
P[H[k]]=k;
P[H[son]]=son;
}
}
inline void UpHeap( int k )
{
for( int key=d[H[k]], f=k/2; k > 1 && d[H[f]] > key; k=f, f/=2 )
{
_swap( H[k], H[f] );
P[H[k]]=k;
P[H[f]]=f;
}
}
inline int pop()
{
int r=H[1];
P[H[N]]=1;
H[1]=H[N];
--N;
DownHeap( 1 );
return r;
}
inline void push( int k, int dis )
{
d[k]=dis;
H[++N]=k;
P[k]=N;
UpHeap( N );
}
int main( void )
{
int n, M, x, y, c;
ifstream in( "dijkstra.in" );
for( in>>n>>M; M; --M )
{
in>>x>>y>>c;
G[x].push_back( mkpr( y, c ) );
}
for( x=1; x <= n; ++x )
d[x]=oo;
for( push( 1, 0 ); N; )
{
x=pop();
isIn[x]=false;
for( it=G[x].begin(), iend=G[x].end(); it < iend; ++it )
{
if( d[it->first] > d[x]+it->second )
{
d[it->first]=d[x]+it->second;
if( false == isIn[it->first] )
{
push( it->first, d[x]+it->second );
isIn[it->first]=true;
}
else UpHeap( P[it->first] );
}
}
}
ofstream out( "dijkstra.out" );
for( x=2; x <= n; ++x )
out<<( oo == d[x] ? 0 : d[x] )<<' ';
out<<'\n';
return EXIT_SUCCESS;
}