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Given a binary tree
struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }
Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL
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Initially, all next pointers are set to NULL
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Note:
For example,
Given the following perfect binary tree,
1 / 2 3 / \ / 4 5 6 7
After calling your function, the tree should look like:
1 -> NULL / 2 -> 3 -> NULL / \ / 4->5->6->7 -> NULL
这道题我采用的是广度优先搜索,采用队列来做,同时记下每一行的结点个数
#include<iostream> #include<queue> using namespace std; //Definition for binary tree with next pointer. struct TreeLinkNode { int val; TreeLinkNode *left, *right, *next; TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {} }; void connect(TreeLinkNode *root) { queue<TreeLinkNode*> temp_queue; if(root==NULL) return; temp_queue.push(root); int row_size=1; while(!temp_queue.empty()) { TreeLinkNode *p1=NULL; TreeLinkNode *p2=NULL; while(row_size>0) { if(row_size==1) { p1=temp_queue.front(); temp_queue.pop(); p1->next=NULL; } else { p1=temp_queue.front(); temp_queue.pop(); p2=temp_queue.front(); p1->next=p2; } row_size--; if(p1->left!=NULL) temp_queue.push(p1->left); if(p1->right!=NULL) temp_queue.push(p1->right); } row_size=temp_queue.size(); } } int main() { TreeLinkNode* root=(TreeLinkNode*)malloc(sizeof(TreeLinkNode)); root->val=1; root->next=NULL; root->left=(TreeLinkNode*)malloc(sizeof(TreeLinkNode)); root->right=(TreeLinkNode*)malloc(sizeof(TreeLinkNode)); root->left->val=2; root->right->val=3; root->left->next=NULL; root->right->next=NULL; connect(root); }
leetcode_116题——Populating Next Right Pointers in Each Node(树,广度优先搜索)
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原文地址:http://www.cnblogs.com/yanliang12138/p/4543481.html