使用C++中一个栈从左到右打印二叉树的叶子节点
程序应该从左到右打印二叉树的叶子节点,但挑战在于只能使用一个栈。
通过push()函数插入二叉树的节点,并通过pop()操作显示叶子节点。
叶子节点是左右指针都为NULL的末端节点,这意味着该节点不是父节点。
示例
Input : 12 21 32 41 59 33 70 Output : 41 59 33 70
栈是一种后进先出(LIFO)的数据结构,其中顶部指针指向最后插入的元素,因此叶子节点将最后插入栈中,并且根据栈的结构,它们将在任何其他节点之前从栈中弹出或移除。
下面的代码显示了使用STL的C++算法实现。
算法
START Step 1 -> create node variable of type structure Declare int data Declare pointer of type node using *left, *right Step 2 -> create function for inserting node with parameter as val Declare node variable of node using malloc Set node->data = val Set node->left = node->right = NULL return node step 3 -> Declare Function void leaf(Node *ptr) create vector stack<Node*>stck Loop While 1 IF ptr Stck.push(ptr) Ptr = ptr->left Else IF (stck.empty()) Break Else IF (stck.top()->right == NULL) Set ptr = stck.top() Set stck.pop() IF ptr->left = NULL Print ptr->data End Loop While ptr == stck.top()->right Set ptr = stck.top() Call stck.pop() IF stck.empty() Break End IF !stck.empty() Set ptr = tck.top()->right Else Set ptr = NULL EndIF End End End Step 4-> In main() Call New passing value user want to insert as Node* root = New(12) Call leaf(root) STOP
示例
#include <bits/stdc++.h> using namespace std; // Structure of a node struct Node { Node* left; Node* right; int data; }; //Function to create a new node Node* New(int val) { Node* node = new Node(); node->left = node->right = NULL; node->data = val; return node; } // leaf node using stack void leaf(Node* ptr) { // stack that will store nodes stack<Node*> stck; while (1) { if (ptr) { stck.push(ptr); ptr = ptr->left; } else { if (stck.empty()) break; else { if (stck.top()->right == NULL) { ptr = stck.top(); stck.pop(); // Print the leaf node if (ptr->left == NULL) printf("%d ", ptr->data); } while (ptr == stck.top()->right) { ptr = stck.top(); stck.pop(); if (stck.empty()) break; } if (!stck.empty()) ptr = stck.top()->right; else ptr = NULL; } } } } int main() { printf("leaf nodes at end level are : "); Node* root = New(12); root->left = New(21); root->right = New(32); root->left->left = New(41); root->left->right = New(59); root->right->left = New(33); root->right->right = New(70); leaf(root); return 0; }
输出
如果运行上述程序,它将生成以下输出。
leaf nodes at end level are : 41 59 33 70
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