编程算法 - 二叉树的最低公共祖先 代码(C)
2017-05-17 19:57 tlnshuju 阅读(304) 评论(0) 编辑 收藏 举报二叉树的最低公共祖先 代码(C)
本文地址: http://blog.csdn.net/caroline_wendy
二叉树的最低公共祖先(lowest common ancestor), 首先先序遍历找到两个结点的路径, 然后依据链表路径找到最低的公共祖先.
代码:
/* * main.cpp * * Created on: 2014.6.12 * Author: Spike */ /*eclipse cdt, gcc 4.8.1*/ #include <iostream> #include <list> #include <queue> using namespace std; struct BinaryTreeNode { BinaryTreeNode(int _value) { value = _value; left = NULL; right = NULL; } int value; BinaryTreeNode* left; BinaryTreeNode* right; }; void printTree (BinaryTreeNode* tree) { BinaryTreeNode* node = tree; std::queue<BinaryTreeNode*> temp1; std::queue<BinaryTreeNode*> temp2; temp1.push(node); while (!temp1.empty()) { node = temp1.front(); if (node->left != NULL) { temp2.push(node->left); } if (node->right != NULL) { temp2.push(node->right); } temp1.pop(); std::cout << node->value << " "; if (temp1.empty()) { std::cout << std::endl; temp1 = temp2; std::queue<BinaryTreeNode*> empty; std::swap(temp2, empty); } } } BinaryTreeNode* buildTree (void) { BinaryTreeNode* root = new BinaryTreeNode(1); BinaryTreeNode* node2 = new BinaryTreeNode(2); BinaryTreeNode* node3 = new BinaryTreeNode(3); BinaryTreeNode* node4 = new BinaryTreeNode(4); BinaryTreeNode* node5 = new BinaryTreeNode(5); BinaryTreeNode* node6 = new BinaryTreeNode(6); BinaryTreeNode* node7 = new BinaryTreeNode(7); BinaryTreeNode* node8 = new BinaryTreeNode(8); BinaryTreeNode* node9 = new BinaryTreeNode(9); BinaryTreeNode* node10 = new BinaryTreeNode(10); root->left = node2; root->right = node3; node2->left = node4; node2->right = node5; node4->left = node6; node4->right = node7; node5->left = node8; node5->right = node9; node9->left = node10; return root; } bool GetNodePath(BinaryTreeNode* root, int v, vector<BinaryTreeNode*>& path) { if (root->value == v) return true; path.push_back(root); bool found = false; if (root->left != NULL && !found) found = GetNodePath(root->left, v, path); if (root->right != NULL && !found) found = GetNodePath(root->right, v, path); if (!found) path.pop_back(); return found; } BinaryTreeNode* GetLastCommonNode ( const vector<BinaryTreeNode*>& path1, const vector<BinaryTreeNode*>& path2) { vector<BinaryTreeNode*>::const_iterator it1 = path1.begin(); vector<BinaryTreeNode*>::const_iterator it2 = path2.begin(); BinaryTreeNode* pLast = NULL; while (it1 != path1.end() && it2 != path2.end()) { if ((*it1)->value == (*it2)->value) pLast = *it1; it1++; it2++; } return pLast; } BinaryTreeNode* GetLastCommonParent(BinaryTreeNode* root, int v1, int v2) { if (root == NULL) return NULL; vector<BinaryTreeNode*> path1; GetNodePath(root, v1, path1); vector<BinaryTreeNode*> path2; GetNodePath(root, v2, path2); return GetLastCommonNode(path1, path2); } int main (void) { BinaryTreeNode* root = buildTree(); int v1 = 6; int v2 = 10; BinaryTreeNode* common = GetLastCommonParent(root, v1, v2); cout << "common node : " << common->value << endl; return 0; }
输出:
common node : 2