LL Rotation, lose the newParent previous right node; RR Rotation too. about dsa.js-data-structures-algorithms-javascript HOT 3 CLOSED

 1                                 1
  \                                 \
   2*                                3
    \    --left-rotation(2)->      /  \
     3                           2*    4
      \
       4

  1*   
   \   
    2  
  /  \ 
 3    4

 16*                                  16*
 / \      --- add two node(8, 2)-->   / \
4  32                                4  32
                                    / \
                                   2  8

     16*                                       16*
     / \                                       / \
    4   32      --- add the node (1)  -->     4  32
   / \                                       / \
  2   8                                     2   8
                                           /
                                          1

rightRotation(16)
function rightRotation(node) {
    const newParent = node.left; // E.g., node 4
    const grandparent = node.parent; // E.g., undefiend 
  
    swapParentChild(node, newParent, grandparent);
  
    newParent.setRightAndUpdateParent(node);
    // we will lose the node 8!
    node.setLeftAndUpdateParent(null);
  
    return newParent;
  }

    4                                            4
   /  \                                         / \
  2   16        --- the correct tree  -->      2  16
 /      \                                     /   / \
1       32                                   1   8  32
rightRotation(16); -- to get right tree;
function rightRotation(node) {
    const newParent = node.left; // E.g., node 4
    const grandparent = node.parent; // E.g., undefiend 
    const previousRight = newParent.right || null;
  
    swapParentChild(node, newParent, grandparent);
  
    newParent.setRightAndUpdateParent(node);
    // we should make the node-8 to be the left of the node-16
    node.setLeftAndUpdateParent(previousRight);
  
    return newParent;
  }