Ejemplo n.º 1
0
void IntervalTree::FixUpMaxHigh(IntervalTreeNode * x) {
  while(x != root) {
    x->maxHigh=ITMax(x->high,ITMax(x->left->maxHigh,x->right->maxHigh));
    x=x->parent;
  }
#ifdef CHECK_INTERVAL_TREE_ASSUMPTIONS
  CheckAssumptions();
#endif
}
Ejemplo n.º 2
0
static void
FixUpMaxHigh(IntervalTree *it, IntervalTreeNode *x)
{
    while(x != it->root) {
        x->maxHigh=ITMax(x->high,ITMax(x->left->maxHigh,x->right->maxHigh));
        x=x->parent;
    }
#ifdef CHECK_INTERVAL_TREE_ASSUMPTIONS
    IT_CheckAssumptions(it);
#endif
}
Ejemplo n.º 3
0
static void
LeftRotate(IntervalTree *it, IntervalTreeNode *x)
{
    IntervalTreeNode *y;
 
    /* I originally wrote this function to use the sentinel for
     * nil to avoid checking for nil.  However this introduces a
     * very subtle bug because sometimes this function modifies
     * the parent pointer of nil.  This can be a problem if a
     * function which calls LeftRotate also uses the nil sentinel
     * and expects the nil sentinel's parent pointer to be unchanged
     * after calling this function.  For example, when DeleteFixUP
     * calls LeftRotate it expects the parent pointer of nil to be
     * unchanged.
     */

    y=x->right;
    x->right=y->left;

    if (y->left != it->nil)
        y->left->parent=x; /* used to use sentinel here */
    /* and do an unconditional assignment instead of testing for nil */
  
    y->parent=x->parent;   

    /* Instead of checking if x->parent is the root as in the book, we
     * count on the root sentinel to implicitly take care of this case
     */
    if (x == x->parent->left)
        x->parent->left=y;
    else
        x->parent->right=y;
    y->left=x;
    x->parent=y;

    x->maxHigh=ITMax(x->left->maxHigh,ITMax(x->right->maxHigh,x->high));
    y->maxHigh=ITMax(x->maxHigh,ITMax(y->right->maxHigh,y->high));
#ifdef CHECK_INTERVAL_TREE_ASSUMPTIONS
    IT_CheckAssumptions(it);
#elif defined(DEBUG_ASSERT)
    Assert(!it->nil->red,"nil not red in ITLeftRotate");
    Assert((it->nil->maxHigh=LONG_MIN),
           "nil->maxHigh != LONG_MIN in ITLeftRotate");
#endif
}
Ejemplo n.º 4
0
void IntervalTree::RightRotate(IntervalTreeNode* y) {
  IntervalTreeNode* x;

  /*  I originally wrote this function to use the sentinel for */
  /*  nil to avoid checking for nil.  However this introduces a */
  /*  very subtle bug because sometimes this function modifies */
  /*  the parent pointer of nil.  This can be a problem if a */
  /*  function which calls LeftRotate also uses the nil sentinel */
  /*  and expects the nil sentinel's parent pointer to be unchanged */
  /*  after calling this function.  For example, when DeleteFixUP */
  /*  calls LeftRotate it expects the parent pointer of nil to be */
  /*  unchanged. */

  x=y->left;
  y->left=x->right;

  if (nil != x->right)  x->right->parent=y; /*used to use sentinel here */
  /* and do an unconditional assignment instead of testing for nil */

  /* instead of checking if x->parent is the root as in the book, we */
  /* count on the root sentinel to implicitly take care of this case */
  x->parent=y->parent;
  if( y == y->parent->left) {
    y->parent->left=x;
  } else {
    y->parent->right=x;
  }
  x->right=y;
  y->parent=x;

  y->maxHigh=ITMax(y->left->maxHigh,ITMax(y->right->maxHigh,y->high));
  x->maxHigh=ITMax(x->left->maxHigh,ITMax(y->maxHigh,x->high));
#ifdef CHECK_INTERVAL_TREE_ASSUMPTIONS
  CheckAssumptions();
#elif defined(DEBUG_ASSERT)
  Assert(!nil->red,"nil not red in ITRightRotate");
  Assert((nil->maxHigh=MIN_INT),
	 "nil->maxHigh != MIN_INT in ITRightRotate");
#endif
}