Leetcode题解 111. Minimum Depth of Binary Tree

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.

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public int minDepth(TreeNode root) {
        if(root==null) return 0;
        else if(root.left==null&&root.right==null){
            return 1;
        }
        return minD(root,1);
    }
    int minD(TreeNode root,int depth){
        if(root.left==null&&root.right==null){
            return depth;
        }
        int left=0x7fffffff;
        int right=0x7fffffff;
        if(root.left!=null){
            left=minD(root.left,depth+1);
        }
        if(root.right!=null){
            right=minD(root.right,depth+1);
        }
        return  min(left,right);
    }
    int min(int a,int b){
        return a>b?b:a;
    }
}