CODEWITHSUNDEEP
javaalgorithmdebuggingbinary-search-tree
sp92
sp92

Reputation: 987

Why won't my solution work to find minimum depth of a binary tree?

I don't understand how my solution for finding minimum depth of a binary tree doesn't work? What am I doing wrong?

Here's a link to the problem if you're curious: https://leetcode.com/problems/minimum-depth-of-binary-tree/submissions/

public int minDepth(TreeNode root) {
    if(root == null) return 0;

    int left = minDepth(root.left);
    int right = minDepth(root.right);

    int ans = Math.min(left, right) + 1;

    return ans;
}

Upvotes: 3

Views: 142

Answers (1)

Déjà vu
Déjà vu

Reputation: 28840

Your code will not work in the case only one side is null, like

  3
 / \
   20
  /  \
 15   7

as it will return 1 (while 3 is not a leaf).

You need to test if one side is null, ignore it and deal with the other side

Upvotes: 2

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