/* -------------------------------------------------------------------
* FUNCTION: Insert
*
* Insert string s at index i.
*
* Time Complexity: O(logN)
* ------------------------------------------------------------------- */
public void Insert(string s, int i)
{
Rope S = new Rope(s);
if (i >= TotalLength) // add s to end
{
Concatenate(S);
}
else if (i <= 0) // add s to beginning
{
S.Concatenate(this);
root = S.root;
}
else // split rope
{
Rope R2 = Split(i);
Concatenate(S);
Concatenate(R2);
}
}
/* -------------------------------------------------------------------
* FUNCTION: Split
*
* Splits a rope into two at index i, returns second rope.
*
* Time Complexity: O(logN)
* ------------------------------------------------------------------- */
public Rope Split(int i)
{
if (i == 0) // no split, return copy of original rope
{
return(this);
}
Rope R2 = new Rope(""); // rope to be returned
Rope Rtemp = new Rope(""); // temp - used for concatenation to R2
Node p = NodeAt(ref i); // find leaf node containing i
Node cur; // used to traverse up tree
if (p != null)
{
if (i > 0) // i is not at start of node
{
// split p into two nodes
p.left = new Node()
{
value = p.value.Substring(0, i),
parent = p,
length = p.value.Substring(0, i).Length
};
p.right = new Node()
{
value = p.value.Substring(i),
parent = p,
length = p.value.Substring(i).Length
};
p.value = null;
p.length = p.left.length;
p = p.right; // set p to right child
}
// move up tree until you're at a right child or root
while (p != root && p == p.parent.left)
{
p = p.parent;
}
cur = p.parent; // keep track of parent node
p.parent = null; // remove link to parent
R2.root = p; // set p to root of new rope
cur.right = null; // cut off node p
// move up tree until you have a new right child
while (cur != root && cur == cur.parent.right)
{
cur = cur.parent;
}
cur = cur.parent;
// continue cutting off right children
while (cur != null && cur.right != null)
{
cur.right.parent = null;
Rtemp.root = cur.right;
R2.Concatenate(Rtemp);
cur.right = null;
// stop loop at right child of root or at root
if (cur != root.right && cur != root)
{
// find new right child
while (cur != root && cur == cur.parent.right)
{
cur = cur.parent;
}
if (cur == root)
{
cur = null;
}
}
}
ReBalance(); // Rebalance the tree starting from root
}
return(R2);
}
