red-black trees to insert the nodewhich is similar to that in ordinary binary search treesbut on keeping the tree balancedso the applet doesn' show the individual steps in the insertion the del button pushing the del button causes the node with the key value typed into the number box to be deleted as with the ins buttonthis deletion takes place immediately after the first pushmultiple pushes are not required the del button and the ins button use the basic insertion algorithms--the same as those in the tree workshop applet this is how the work is divided between the applet and the userthe applet does the insertionbut it' (mostlyup to the user to make the appropriate changes to the tree to ensure the red-black rules are followed and the tree thereby becomes balanced the flip button if there is black parent with two red childrenand you place the red arrow on the parent by clicking on the node with the mousethen when you press the flip buttonthe parent will become red and the children will become black that isthe colors are flipped between the parent and children you'll learn later why such color exchange is desirable if you try to flip the rootit will remain blackso as not to violate rule but its children will change from red to black the rol button the rol button carries out left rotation to rotate group of nodesfirst singleclick the mouse to position the arrow at the topmost node of the group to be rotated for left rotationthe top node must have right child then click the button we'll examine rotations in detail later the ror button the ror button performs right rotation position the arrow on the top node to be rotatedmaking sure it has left childthen click the button the / button the / button changes red node to blackor black node to red single-click the mouse to position the red arrow on the nodeand then push the button (this button changes the color of single nodedon' confuse it with the flip buttonwhich changes three nodes at once