求二叉樹中任意兩個結點間的路徑（C++）
阿新 • • 發佈：2018-12-11
方法一
#include <iostream> #include <vector> using namespace std; struct Node { int val; Node* left; Node* right; Node(int v) { val = v; left = nullptr; right = nullptr; } }; void GetNodePath(Node* root, Node* node, vector<Node*>& v, bool& flag) //用後根遍歷的方式尋找node，找到後儲存從該節點到根節點的路徑 { if (root == NULL || flag == true)//根為空或者node已經找到了 return; GetNodePath(root->left, node, v, flag); GetNodePath(root->right, node, v, flag); if (root->val == node->val || flag == true)//找到node或者root為node到根節點路徑上的節點 { v.push_back(root);//儲存從node到根節點的路徑 flag = true; } } Node* CreatTree()//初始化樹 { Node* root = new Node(1); Node* node1 = new Node(2); Node* node2 = new Node(3); Node* node3 = new Node(4); Node* node4 = new Node(5); Node* node5 = new Node(6); Node* node6 = new Node(7); root->left = node1; root->right = node2; node1->left = node3; node1->right = node4; node2->left = node5; node2->right = node6; return root; } int main() { Node* root = CreatTree(); Node* node1 = new Node(5); Node* node2 = new Node(6); bool flag = false; vector<Node*> path1;//用於記錄路徑 vector<Node*> path2; GetNodePath(root, node1, path1, flag); flag = false; GetNodePath(root, node2, path2, flag); //下面程式碼用於求兩個連結串列的第一個公共節點 int i = 0, j = 0; if (path1.size() > path2.size()) i = path1.size() - path2.size(); else j = path2.size() - path1.size(); int res = -1; while (i < path1.size() && j < path2.size()) { if (path1[i]->val == path2[j]->val) { res = path1[i]->val; break; } i++; j++; } cout << res << endl; cout << i + j; cout << endl; system("pause"); return 0; }
方法二
#include <iostream> #include <vector> using namespace std; struct Node { int val; Node* left; Node* right; Node(int v) { val = v; left = nullptr; right = nullptr; } }; Node* CreatTree() { Node* root = new Node(1); Node* node1 = new Node(2); Node* node2 = new Node(3); Node* node3 = new Node(4); Node* node4 = new Node(5); Node* node5 = new Node(6); Node* node6 = new Node(7); root->left = node1; root->right = node2; node1->left = node3; node1->right = node4; node2->left = node5; node2->right = node6; return root; } Node* FindFather(Node* root, Node* node1, Node* node2, int& flag) { if (flag == 2) return nullptr; if (root == nullptr) return nullptr; Node* left = FindFather(root->left, node1, node2, flag); Node* right = FindFather(root->right, node1, node2, flag); if (left && right) return root; if (root->val == node1->val) { flag++; return root; } if (root->val == node2->val) { flag++; return root; } if (left == nullptr && right) return right; if (right == nullptr && left) return left; return nullptr; } int FindPath(Node* root, Node* node, int &flag) { if (flag == 1) return -1; if (root == nullptr || node == nullptr) return -1; if (root->val == node->val) { flag = 1; return 0; } int left = FindPath(root->left, node, flag); int right = FindPath(root->right, node, flag); if (left >= 0) return left + 1; else if (right >= 0) return right + 1; else return -1; } int main() { Node* root = CreatTree(); Node* node1 = new Node(6); Node* node2 = new Node(5); int flag = 0; Node* father = FindFather(root, node1, node2, flag); int flag1 = 0, flag2 = 0; cout << FindPath(father, node1, flag1) + FindPath(father, node2, flag2) << endl; system("pause"); return 0; }