LeetCode 111
Minimum Depth of Binary Tree
- Problem Description:
給出一棵二叉樹,輸出二叉樹中從根節點到最近葉節點所經過的節點數。
具體的題目資訊:
https://leetcode.com/problems/minimum-depth-of-binary-tree/description/
- Example:
LeetCode 111 Minimum Depth of Binary TreeLeetCode 111 - Solution:
-
解題思路:
通過二叉樹的層次周遊實作,當周遊過程中發現第一個葉節點(即距離根節點最近的葉節點),輸出目前的層數即可。
- 程式設計實作:
-
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int minDepth(TreeNode* root) {
if (root == NULL) return ;
if (root->left == NULL&&root->right == NULL) return ;
TreeNode* node[];
int front = -, rear = -;
int last = , level = , flag = ;
node[++rear] = root;
while(front<rear) {
TreeNode* temp = node[++front];
if (temp->left == NULL&&temp->right == NULL) {
level++;
break;
}
if (temp->left) {
node[++rear] = temp->left;
}
if (temp->right) {
node[++rear] = temp->right;
}
if (front == last) {
level++;
last = rear;
}
}
return level;
}
};