LeetCode(111) Minimum Depth of Binary Tree解题报告

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.

解题思路:

递归求解，如果有比min还小的深度，就更新min，需要注意的是，最小深度是叶子节点到根节点的深度。如果左子树或右子树为空，那么这个就不能计算在内。

public class Solution {
int min;
public int minDepth(TreeNode root) {
min = Integer.MAX_VALUE;
DepthOfTree(root,0);
return min;
}
public void DepthOfTree(TreeNode root,int depth){
if(root == null){
if(min > depth)
min = depth;
return ;
}
if(root.left == null)
DepthOfTree(root.right,depth+1);
else if(root.right == null)
DepthOfTree(root.left,depth+1);
else{
DepthOfTree(root.left,depth+1);
DepthOfTree(root.right,depth+1);
}
}
}