Minimum Depth of Binary Tree [LeetCode]

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.

Summary: BFS or DFS with recursion.

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