题目:
给定二叉树,找到它的最小深度。
The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.
最小深度是沿从根节点到最近的叶节点的最短路径上的节点数。
Note: A leaf is a node with no children.
注意:叶子是没有子节点的节点。
Example:
二叉树: [3,9,20,null,null,15,7],
3
/ \
9 20
/ \
15 7
return its minimum depth = 2.
public class Minimumdepth {
public class TreeNode{
TreeNode left;
TreeNode right;
int val;
public void TreeNode(int val){
this.val = val;
}
}
public class Solution {
public int run(TreeNode root) {
if(root == null){
return 0;
}
int left = run(root.left);
int right = run(root.right);
return (left == 0 || right == 0) ? left + right + 1 : Math.min(left, right) + 1;
}
}
public static void main(String[] args) {
}
}