mirror of
https://gitlab.com/freepascal.org/lazarus/lazarus.git
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avglvltree: replaced recursion with simple loop
git-svn-id: trunk@36134 -
This commit is contained in:
mattias
parent
c41894692e
commit
ef5ef38048
@ -830,135 +830,134 @@ var
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OldRightLeftLeft, OldRightLeftRight, OldLeftRightLeft, OldLeftRightRight
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OldRightLeftLeft, OldRightLeftRight, OldLeftRightLeft, OldLeftRightRight
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: TAvgLvlTreeNode;
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: TAvgLvlTreeNode;
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begin
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begin
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if (ANode=nil) then exit;
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while ANode<>nil do begin
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if ((ANode.Balance=+1) or (ANode.Balance=-1)) then exit;
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if ((ANode.Balance=+1) or (ANode.Balance=-1)) then exit;
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OldParent:=ANode.Parent;
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OldParent:=ANode.Parent;
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if (ANode.Balance=0) then begin
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if (ANode.Balance=0) then begin
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// Treeheight has decreased by one
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// Treeheight has decreased by one
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if (OldParent<>nil) then begin
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if (OldParent=nil) then
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exit;
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if(OldParent.Left=ANode) then
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if(OldParent.Left=ANode) then
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Inc(OldParent.Balance)
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Inc(OldParent.Balance)
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else
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else
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Dec(OldParent.Balance);
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Dec(OldParent.Balance);
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BalanceAfterDelete(OldParent);
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ANode:=OldParent;
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end;
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end else if (ANode.Balance=+2) then begin
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exit;
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// Node is overweighted to the right
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end;
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OldRight:=ANode.Right;
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if (ANode.Balance=+2) then begin
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if (OldRight.Balance>=0) then begin
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// Node is overweighted to the right
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// OldRight.Balance is 0 or -1
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OldRight:=ANode.Right;
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// rotate left
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if (OldRight.Balance>=0) then begin
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OldRightLeft:=OldRight.Left;
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// OldRight.Balance is 0 or -1
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if (OldParent<>nil) then begin
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// rotate left
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if (OldParent.Left=ANode) then
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OldRightLeft:=OldRight.Left;
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OldParent.Left:=OldRight
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if (OldParent<>nil) then begin
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else
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if (OldParent.Left=ANode) then
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OldParent.Right:=OldRight;
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OldParent.Left:=OldRight
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end else
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fRoot:=OldRight;
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ANode.Parent:=OldRight;
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ANode.Right:=OldRightLeft;
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OldRight.Parent:=OldParent;
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OldRight.Left:=ANode;
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if (OldRightLeft<>nil) then
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OldRightLeft.Parent:=ANode;
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ANode.Balance:=(1-OldRight.Balance); // toggle 0 and 1
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Dec(OldRight.Balance);
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ANode:=OldRight;
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end else begin
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// OldRight.Balance=-1
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// double rotate right left
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OldRightLeft:=OldRight.Left;
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OldRightLeftLeft:=OldRightLeft.Left;
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OldRightLeftRight:=OldRightLeft.Right;
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if (OldParent<>nil) then begin
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if (OldParent.Left=ANode) then
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OldParent.Left:=OldRightLeft
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else
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OldParent.Right:=OldRightLeft;
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end else
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fRoot:=OldRightLeft;
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ANode.Parent:=OldRightLeft;
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ANode.Right:=OldRightLeftLeft;
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OldRight.Parent:=OldRightLeft;
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OldRight.Left:=OldRightLeftRight;
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OldRightLeft.Parent:=OldParent;
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OldRightLeft.Left:=ANode;
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OldRightLeft.Right:=OldRight;
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if (OldRightLeftLeft<>nil) then
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OldRightLeftLeft.Parent:=ANode;
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if (OldRightLeftRight<>nil) then
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OldRightLeftRight.Parent:=OldRight;
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if (OldRightLeft.Balance<=0) then
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ANode.Balance:=0
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else
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else
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OldParent.Right:=OldRight;
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ANode.Balance:=-1;
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end else
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if (OldRightLeft.Balance>=0) then
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fRoot:=OldRight;
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OldRight.Balance:=0
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ANode.Parent:=OldRight;
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else
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ANode.Right:=OldRightLeft;
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OldRight.Balance:=+1;
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OldRight.Parent:=OldParent;
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OldRightLeft.Balance:=0;
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OldRight.Left:=ANode;
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ANode:=OldRightLeft;
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if (OldRightLeft<>nil) then
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end;
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OldRightLeft.Parent:=ANode;
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ANode.Balance:=(1-OldRight.Balance); // toggle 0 and 1
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Dec(OldRight.Balance);
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BalanceAfterDelete(OldRight);
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end else begin
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end else begin
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// OldRight.Balance=-1
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// Node.Balance=-2
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// double rotate right left
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// Node is overweighted to the left
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OldRightLeft:=OldRight.Left;
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OldLeft:=ANode.Left;
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OldRightLeftLeft:=OldRightLeft.Left;
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if (OldLeft.Balance<=0) then begin
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OldRightLeftRight:=OldRightLeft.Right;
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// rotate right
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if (OldParent<>nil) then begin
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OldLeftRight:=OldLeft.Right;
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if (OldParent.Left=ANode) then
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if (OldParent<>nil) then begin
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OldParent.Left:=OldRightLeft
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if (OldParent.Left=ANode) then
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OldParent.Left:=OldLeft
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else
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OldParent.Right:=OldLeft;
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end else
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fRoot:=OldLeft;
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ANode.Parent:=OldLeft;
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ANode.Left:=OldLeftRight;
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OldLeft.Parent:=OldParent;
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OldLeft.Right:=ANode;
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if (OldLeftRight<>nil) then
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OldLeftRight.Parent:=ANode;
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ANode.Balance:=(-1-OldLeft.Balance); // toggle 0 and -1
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Inc(OldLeft.Balance);
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ANode:=OldLeft;
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end else begin
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// OldLeft.Balance = 1
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// double rotate left right
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OldLeftRight:=OldLeft.Right;
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OldLeftRightLeft:=OldLeftRight.Left;
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OldLeftRightRight:=OldLeftRight.Right;
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if (OldParent<>nil) then begin
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if (OldParent.Left=ANode) then
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OldParent.Left:=OldLeftRight
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else
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OldParent.Right:=OldLeftRight;
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end else
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fRoot:=OldLeftRight;
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ANode.Parent:=OldLeftRight;
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ANode.Left:=OldLeftRightRight;
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OldLeft.Parent:=OldLeftRight;
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OldLeft.Right:=OldLeftRightLeft;
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OldLeftRight.Parent:=OldParent;
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OldLeftRight.Left:=OldLeft;
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OldLeftRight.Right:=ANode;
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if (OldLeftRightLeft<>nil) then
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OldLeftRightLeft.Parent:=OldLeft;
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if (OldLeftRightRight<>nil) then
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OldLeftRightRight.Parent:=ANode;
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if (OldLeftRight.Balance>=0) then
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ANode.Balance:=0
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else
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else
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OldParent.Right:=OldRightLeft;
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ANode.Balance:=+1;
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end else
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if (OldLeftRight.Balance<=0) then
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fRoot:=OldRightLeft;
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OldLeft.Balance:=0
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ANode.Parent:=OldRightLeft;
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ANode.Right:=OldRightLeftLeft;
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OldRight.Parent:=OldRightLeft;
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OldRight.Left:=OldRightLeftRight;
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OldRightLeft.Parent:=OldParent;
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OldRightLeft.Left:=ANode;
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OldRightLeft.Right:=OldRight;
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if (OldRightLeftLeft<>nil) then
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OldRightLeftLeft.Parent:=ANode;
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if (OldRightLeftRight<>nil) then
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OldRightLeftRight.Parent:=OldRight;
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if (OldRightLeft.Balance<=0) then
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ANode.Balance:=0
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else
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ANode.Balance:=-1;
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if (OldRightLeft.Balance>=0) then
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OldRight.Balance:=0
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else
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OldRight.Balance:=+1;
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OldRightLeft.Balance:=0;
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BalanceAfterDelete(OldRightLeft);
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end;
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end else begin
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// Node.Balance=-2
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// Node is overweighted to the left
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OldLeft:=ANode.Left;
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if (OldLeft.Balance<=0) then begin
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// rotate right
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OldLeftRight:=OldLeft.Right;
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if (OldParent<>nil) then begin
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if (OldParent.Left=ANode) then
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OldParent.Left:=OldLeft
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else
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else
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OldParent.Right:=OldLeft;
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OldLeft.Balance:=-1;
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end else
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OldLeftRight.Balance:=0;
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fRoot:=OldLeft;
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ANode:=OldLeftRight;
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ANode.Parent:=OldLeft;
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end;
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ANode.Left:=OldLeftRight;
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OldLeft.Parent:=OldParent;
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OldLeft.Right:=ANode;
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if (OldLeftRight<>nil) then
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OldLeftRight.Parent:=ANode;
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ANode.Balance:=(-1-OldLeft.Balance); // toggle 0 and -1
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Inc(OldLeft.Balance);
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BalanceAfterDelete(OldLeft);
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end else begin
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// OldLeft.Balance = 1
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// double rotate left right
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OldLeftRight:=OldLeft.Right;
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OldLeftRightLeft:=OldLeftRight.Left;
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OldLeftRightRight:=OldLeftRight.Right;
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if (OldParent<>nil) then begin
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if (OldParent.Left=ANode) then
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OldParent.Left:=OldLeftRight
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else
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OldParent.Right:=OldLeftRight;
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end else
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fRoot:=OldLeftRight;
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ANode.Parent:=OldLeftRight;
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ANode.Left:=OldLeftRightRight;
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OldLeft.Parent:=OldLeftRight;
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OldLeft.Right:=OldLeftRightLeft;
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OldLeftRight.Parent:=OldParent;
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OldLeftRight.Left:=OldLeft;
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OldLeftRight.Right:=ANode;
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if (OldLeftRightLeft<>nil) then
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OldLeftRightLeft.Parent:=OldLeft;
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if (OldLeftRightRight<>nil) then
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OldLeftRightRight.Parent:=ANode;
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if (OldLeftRight.Balance>=0) then
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ANode.Balance:=0
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else
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ANode.Balance:=+1;
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if (OldLeftRight.Balance<=0) then
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OldLeft.Balance:=0
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else
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OldLeft.Balance:=-1;
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OldLeftRight.Balance:=0;
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BalanceAfterDelete(OldLeftRight);
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end;
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end;
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end;
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end;
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end;
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end;
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