void topo_dfs (int node) {
vis[node] = 1;
for (int i = 1; i <= n; ++i) {
if (map[node][i] && !vis[i]) {
topo_dfs(i);
}
}
topo_list[++cnt_topo_list] = node;
}
void topo_sort (void) {
memset(topo_list, 0, sizeof(topo_list));
cnt_topo_list = 0;
memset(vis, 0, sizeof(vis));
for (int i = 1; i <= n; ++i) {
if (!vis[i]) {
topo_dfs(i);
}
}
}
int main()
{
int n1, n2, i;
int* tptr;
/* read in the number of nodes */
scanf( "%d", &numNodes );
/* initialize */
for ( i = 0; i < numNodes; i++ )
{
allNodes[i].numAdj = 0;
allNodes[i].adj = NULL;
val[i] = 0;
}
/* read in the edges in the dag */
while( scanf( "%d%d", &n1, &n2 ) == 2 )
{
tptr = realloc( allNodes[n1].adj,
allNodes[n1].numAdj * sizeof( int ) );
if ( !tptr )
{
fprintf( stderr, "Out of memory, exiting.\n" );
exit( 1 );
}
allNodes[n1].adj = tptr;
allNodes[n1].adj[allNodes[n1].numAdj++] = n2;
}
/* MUST INITIALIZE topoIndex to the end of the topo array */
topoIndex = numNodes - 1;
/* call the dfs procedure on each connected component */
for ( i = 0; i < numNodes; i++ )
{
if ( !val[i] )
{
topo_dfs( i );
}
}
/* print out the results */
for ( i = 0; i < numNodes; i++ )
{
printf( "%d ", topo[i] );
}
printf( "\n" );
return 0;
}
void topo_dfs( int k )
{
int next;
/* mark this node as having been visited */
val[k] = ++id;
/* look at all nodes adjecent to the current node */
for ( next = 0; next < allNodes[k].numAdj; next++ )
{
if ( !val[allNodes[k].adj[next]] )
{
/* recurse if the node has not been visited before */
topo_dfs( allNodes[k].adj[next] );
}
}
/* the current node is adjacent to no more unvisited nodes, so put
it in the list, in the unused position closest to the end */
topo[topoIndex--] = k;
}
