Minimum Depth of Binary Tree

Minimum Depth of Binary Tree

Total Accepted: 84038 Total Submissions: 283068 Difficulty: Easy

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.

 (E) Binary Tree Level Order Traversal (E) Maximum Depth of Binary Tree

 

/**
 * 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 0;
        int lh = minDepth(root->left);
        int rh = minDepth(root->right);
        if(lh==0 && rh==0){//左右子树都空
            return 1;
        }
        if(lh==0){//左子树空
            return rh+1;
        }
        if(rh==0){//右子树空
            return lh+1;
        }
        return lh<rh ? lh+1:rh+1;//左右子树都不空
    }
};

Next challenges: (E) Binary Tree Level Order Traversal