Find the minimum common parent node of the two nodes in the binary tree.

Algorithm Design: traverse the binary tree and put the parent nodes of the two nodes into two linked lists respectively. Then, compare them sequentially to find the last same node, which is the lowest common node.

 

C pseudo code implementation:

List * h, * h1, * h2; bool find1 = false, find2 = false; void postVisit (BTNode * root) {if (root! = Null) {add (root, h); // add the root node to the postVisit (root-> lchild) linked list with h as the header; if (root-> lchild! = NULL) delete (root-> lchild, h); // delete the right root child node postVisit (root-> lchild) from the h linked list; if (root-> rchild! = NULL) delete (root-> rchild, h); // delete the left-Child root node from the h linked list if (root-> value = v1) {copy (h, h1); // find the first required node and copy all the nodes in the h linked list to find1 = true;} else (root-> value = v1) In h1 )) {copy (h, h2); // find the second required node and copy all nodes in the h linked list to find2 = true;} if (find1 & find2) // two linked lists are formed and returned sequentially after exiting;} void findParentNode (BTNode * root) {postVisit (root); for (List * p1 = h1, * p2 = h2; p1-> next-> node! = P2-> next-> node & p1! = NULL & p2! = NULL; p1 = p1-> next, p2 = p2-> next); if (p1-> node! = P2-> node) // No public node is found at this time, and the target node printf ("not same parent"); else printf (p1-> node) may not be found ); // output the lowest public node}