Pagini recente » Cod sursa (job #391276) | Cod sursa (job #1020827) | Cod sursa (job #2207398) | Cod sursa (job #1184370) | Cod sursa (job #2009216)
#include<cstdio>
#include<vector>
#define MAX_N 50000
#define oo 0x3f3f3f3f
using namespace std;
vector<pair<int, int>> G[MAX_N+1];
int dist[MAX_N+1], h[MAX_N+1], pos[MAX_N+1], n, m, k;
inline void Swap(int i, int j)
{
int aux = h[i];
h[i] = h[j];
h[j] = aux;
aux = pos[h[i]];
pos[h[i]] = pos[h[j]];
pos[h[j]] = aux;
}
void heapDown(int i)
{
if(2*i > k) return;
int l, r;
l = dist[h[2*i]];
if(2*i+1 <= k)
r = dist[h[2*i+1]];
else r = l + 1;
if(l < r)
{
if(dist[h[i]] <= l) return;
Swap(i,2*i);
heapDown(2*i);
}
else
{
if(dist[h[i]] <= r) return;
Swap(i,2*i+1);
heapDown(2*i+1);
}
}
void heapUp(int i)
{
if(dist[h[i/2]] <= dist[h[i]]) return;
Swap(i,i/2);
heapUp(i/2);
}
void Dijkstra(int source)
{
int i, Node;
vector<pair<int, int>>::iterator it;
for(i=1; i<=n; i++)
{
dist[i] = oo;
h[i] = pos[i] = i;
}
k = n;
dist[source] = 0;
for(i=1; i<=n; i++)
{
Node = h[1];
Swap(1,k);
k--;
heapDown(1);
for(it = G[Node].begin(); it != G[Node].end(); it++)
if(dist[(*it).first] > dist[Node] + (*it).second)
{
dist[(*it).first] = dist[Node] + (*it).second;
heapUp(pos[(*it).first]);
}
}
}
int main()
{
int i, x, y, cost;
FILE *fin, *fout;
fin = fopen("dijkstra.in","r");
fout = fopen("dijkstra.out","w");
fscanf(fin,"%d%d",&n,&m);
for(i=1; i<=m; i++)
{
fscanf(fin,"%d%d%d",&x,&y,&cost);
G[x].push_back(make_pair(y,cost));
}
fclose(fin);
Dijkstra(1);
for(i=2; i<=n; i++)
if(dist[i] != oo)
fprintf(fout,"%d ",dist[i]);
else fprintf(fout,"0 ");
fprintf(fout,"\n");
fclose(fout);
return 0;
}