Minimum Depth Of Binary Tree Problem


Description

LeetCode Problem 111.

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.

Note: A leaf is a node with no children.

Example 1:

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Input: root = [3,9,20,null,null,15,7]
Output: 2

Example 2:

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Input: root = [2,null,3,null,4,null,5,null,6]
Output: 5

Constraints:

  • The number of nodes in the tree is in the range [0, 10^5].
  • -1000 <= Node.val <= 1000


Sample C++ Code

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class Solution {
public:
    int minDepth(TreeNode* root) {
        if (root == NULL)
            return 0;
        if ((root->left == NULL) && (root->right == NULL))
            return 1;
        else if (root->left == NULL)
            return minDepth(root->right) + 1;
        else if (root->right == NULL)
            return minDepth(root->left) + 1;
        else 
            return min(minDepth(root->left), minDepth(root->right)) + 1;
    }
};




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