二叉树中任意两个节点间的距离 源码

#include <iostream>
#include <list>

template<typename T> struct BNode {

    BNode(T d) {
        data = d;
        left = NULL;
        right = NULL;
    }

    void visit() {
        std::cout << data << std::endl;
    }

    T data;
    BNode<T> *left;
    BNode<T> *right;
};

// 获取访问路径
template<typename T> std::list<BNode<T>*>* getPath(BNode<T> *root, BNode<T> *node) {
    if (root && node) {
        std::list<BNode<T>*> *pList = new std::list<BNode<T>*>();
        for (BNode<T> *iter = root; !pList->empty() || iter != NULL;) {
            while (iter) {
                pList->push_back(iter);
                if (iter == node) {
                    return pList;
                }
                iter = iter->left;
            }
            while (!pList->empty() && iter == pList->back()->right) {
                iter = pList->back();
                pList->pop_back();
            }
            if (!pList->empty()) {
                iter = pList->back()->right;
            }
        }
    }
    return NULL;
}

// 计算任意两个节点间的距离
template<typename T> int distance(BNode<T> *root, BNode<T> *node1, BNode<T> *node2) {
    if (root && node1 && node2) {
        std::list<BNode<T>*> *pList1 = getPath<T>(root, node1);
        std::list<BNode<T>*> *pList2 = getPath<T>(root, node2);
        while (pList1->front() == pList2->front()) {
            pList1->pop_front();
            pList2->pop_front();
        }
        size_t len = pList1->size() + pList2->size();
        delete pList1;
        delete pList2;
        return len;
    }
    return 0;
}

// 测试代码
int main() {
    typedef BNode<char> BCharNode;

    BCharNode root('A');
    BCharNode nodeB('B');
    BCharNode nodeD('D');
    BCharNode nodeE('E');
    nodeB.left = &nodeD;
    nodeB.right = &nodeE;
    BCharNode nodeC('C');
    BCharNode nodeF('F');
    BCharNode nodeG('G');
    nodeC.left = &nodeF;
    nodeC.right = &nodeG;
    root.left = &nodeB;
    root.right = &nodeC;

    /*std::list<BCharNode*>* pList = getPath<char>(&root, &nodeF);
     for (std::list<BCharNode*>::iterator iter = pList->begin(); iter != pList->end(); ++iter) {
     (*iter)->visit();
     }
     delete pList;*/
    std::cout << distance<char>(&root, &nodeF, &nodeG) << std::endl;
    return 0;
}