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Cod sursa(job #447043)
/*
* File: main.cpp
* Author: virtualdemon
*
* Created on April 26, 2010, 8:50 PM
*/
#include <vector>
#include <cstdlib>
#include <fstream>
#include <algorithm>
#define Nmax 50011
#define oo 0x3f3f3f3f
/*
*
*/
using namespace std;
typedef pair< int, int > pr;
int N;
int H[Nmax], P[Nmax], d[Nmax];
vector< pr > G[Nmax];
vector< pr >::const_iterator it, iend;
inline void DownHeap( int k )
{
for( int son=2*k; son <= N; k=son, son*=2 )
{
if( son < N && d[H[son+1]] < d[H[son]] )
++son;
if( d[H[k]] <= d[H[son]] )
return;
swap( H[k], H[son] );
swap( P[H[k]], P[H[son]] );
}
}
inline void UpHeap( int k )
{
for( int key=d[H[k]], f=k/2; k > 1 && key < d[H[f]]; k=f, f/=2 )
{
swap( H[k], H[f] );
swap( P[H[k]], P[H[f]] );
}
}
inline int pop( void )
{
int r=H[1];
P[H[1]]=0;
H[1]=H[N];
--N;
DownHeap(1);
return r;
}
inline void push( int k )
{
H[++N]=k;
P[k]=N;
UpHeap( N );
}
int main(int argc, char** argv)
{
int M, x, y, c;
ifstream in( "dijkstra.in" );
for( in>>N>>M; M; --M )
{
in>>x>>y>>c;
G[x].push_back( pr( y, c ) );
}
M=N;
fill( d+2, d+N+1, oo );
for( N=0, push(1); N; )
{
x=pop();
for( it=G[x].begin(), iend=G[x].end(); it < iend; ++it )
{
y=it->first, c=it->second;
if( d[y] > d[x]+c )
{
d[y]=d[x]+c;
if( !P[y] )
{
push(y);
}
else UpHeap( P[y] );
}
}
}
ofstream out( "dijkstra.out" );
for( x=2; x <= M; ++x )
if( oo == d[x] )
out<<"0 ";
else out<<d[x]<<' ';
return (EXIT_SUCCESS);
}