diff options
Diffstat (limited to 'py/pairheap.h')
| -rw-r--r-- | py/pairheap.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/py/pairheap.h b/py/pairheap.h index 8a9138b17..16ae78809 100644 --- a/py/pairheap.h +++ b/py/pairheap.h @@ -35,6 +35,7 @@ // Algorithmica 1:111-129, 1986. // https://www.cs.cmu.edu/~sleator/papers/pairing-heaps.pdf +#include <assert.h> #include "py/obj.h" // This struct forms the nodes of the heap and is intended to be extended, by @@ -77,14 +78,16 @@ static inline mp_pairheap_t *mp_pairheap_peek(mp_pairheap_lt_t lt, mp_pairheap_t // Push new node onto existing heap. Returns the new heap. static inline mp_pairheap_t *mp_pairheap_push(mp_pairheap_lt_t lt, mp_pairheap_t *heap, mp_pairheap_t *node) { - node->child = NULL; - node->next = NULL; + assert(node->child == NULL && node->next == NULL); return mp_pairheap_meld(lt, node, heap); // node is first to be stable } // Pop the top off the heap, which must not be empty. Returns the new heap. static inline mp_pairheap_t *mp_pairheap_pop(mp_pairheap_lt_t lt, mp_pairheap_t *heap) { - return mp_pairheap_pairing(lt, heap->child); + assert(heap->next == NULL); + mp_pairheap_t *child = heap->child; + heap->child = NULL; + return mp_pairheap_pairing(lt, child); } #endif // MICROPY_INCLUDED_PY_PAIRHEAP_H |