Minimum Depth of Binary Tree leetcode java

本文轉載自查看原文 2014-07-31 00:47 2931 leetcode每題整理

題目：

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

題解：

遞歸解法急速判斷左右兩邊子樹哪個depth最小，要注意如果有個節點只有一邊孩子時，不能返回0，要返回另外一半邊的depth。

遞歸解法：

1      public int minDepth(TreeNode root) {
2          if(root == null)
3              return 0;
4          int minleft = minDepth(root.left);
5          int minright = minDepth(root.right);
6          if(minleft==0 || minright==0)
7              return minleft>=minright?minleft+1:minright+1;
8          return Math.min(minleft,minright)+1;
9     }

非遞歸解法：

1      public int minDepth(TreeNode root) {
2          if(root == null)
3              return 0;
4
5          int depth = 1;//The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.
6         LinkedList<TreeNode> queue = new LinkedList<TreeNode>();
7         queue.add(root);
8          int curnum = 1;
9          int nextnum = 0;
10          while(!queue.isEmpty()){
11             TreeNode cur = queue.poll();
12             curnum--;
13
14              if(cur.left == null && cur.right == null)
15                  return depth;
16
17              if(cur.left != null){
18                queue.add(cur.left);
19                nextnum++;
20             }
21
22              if(cur.right != null){
23                 queue.add(cur.right);
24                 nextnum++;
25             }
26
27              if(curnum == 0){
28                 curnum = nextnum;
29                 nextnum = 0;
30                 depth++;
31             }
32         }
33          return depth;
34     }

免責聲明！

本站轉載的文章為個人學習借鑒使用，本站對版權不負任何法律責任。如果侵犯了您的隱私權益，請聯系本站郵箱yoyou2525@163.com刪除。

猜您在找 [LeetCode] Minimum Depth of Binary Tree LeetCode:Minimum Depth of Binary Tree,Maximum Depth of Binary Tree [leetcode]Minimum Depth of Binary Tree @ Python [LeetCode] 111. Minimum Depth of Binary Tree 二叉樹的最小深度 LeetCode：111_Minimum Depth of Binary Tree | 二叉樹的最小深度 | Easy [leetcode]Maximum Depth of Binary Tree @ Python Flatten Binary Tree to Linked List leetcode java Binary Tree Maximum Path Sum leetcode java Binary Tree Level Order Traversal leetcode java Binary Tree Inorder Traversal leetcode java