111. Minimum Depth of Binary Tree & 104. Maximum Depth of Binary Tree

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. * 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) return 0;        int left = minDepth(root->left);        int right = minDepth(root->right);        if(right == 0 || left == 0){            return 1 + left + right;        }else {            return 1+min(left,right);        }    }};

104. Maximum Depth of Binary Tree

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

class Solution {public:    int maxDepth(TreeNode* root) {        if(!root) return 0;        int left = maxDepth(root->left);        int right = maxDepth(root->right);        if(right == 0 || left == 0){            return 1 + left + right;        }else {            return 1+max(left,right);        }    }};