Minimum Depth of Binary Tree LeetCode solution in C++

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class Solution {
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 public:
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  void maxlevel(TreeNode *root, int level, int &ans) {
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    if (!root) return;
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    if (!root->left && !root->right) {
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      ans = min(level, ans);
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      return;
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    }
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    maxlevel(root->left, level + 1, ans);
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    maxlevel(root->right, level + 1, ans);
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  }
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  int minDepth(TreeNode *root) {
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    if (!root) return 0;
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    int ans = INT_MAX;
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    maxlevel(root, 0, ans);
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    return ans + 1;
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  }
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};