[Home]
[Contents]
[Chapter]
[Previous Algorithm]
[Next Algorithm]

Binary priority queues deletion (Pascal version available)


tree delete( pq ) tree pq; {tree temp; if ( pq == NULL ) Error /*** deletion on an empty queue ***/; else if ( pq->right == NULL ) return( pq->left ); else { /*** promote left descendant up ***/ pq->k = pq->left->k; pq->left = delete( pq->left ); /*** rearrange according to constraints ***/ if ( pq->left == NULL ) { pq->left = pq->right; pq->right = NULL; }; if ( pq->right != NULL ) if ( pq->left->k < pq->right->k ) { /*** descendants in wrong order ***/ temp = pq->right; pq->right = pq->left; pq->left = temp; } return( pq ); } };

C source (516b.del.c) Pascal source (516b.del.p)


© Addison-Wesley Publishing Co. Inc.