Binary Tree Right Side View LeetCode solution in Java

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class Solution {
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  // Utility Function of RightSideView
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  public void rightView(TreeNode curr, List<Integer> list, int level) {
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    // if, current is null, return
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    if (curr == null) {
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      return;
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    }
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    // if, level = list size
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    // add current val to list
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    if (level == list.size()) {
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      list.add(curr.val);
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    }
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    // recursive call for right side view
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    rightView(curr.right, list, level + 1);
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    // recursive call for left side view
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    rightView(curr.left, list, level + 1);
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  }
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  // Binary Tree Right Side View Function
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  public List<Integer> rightSideView(TreeNode root) {
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    // create a list
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    List<Integer> result = new ArrayList<>();
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    // call right view function
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    rightView(root, result, 0);
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    return result;
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  }
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}
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// Output -
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/*
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Input: root = [1,2,3,null,5,null,4]
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Output: [1,3,4]
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*/
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// Time & Space Complexity -
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/*
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Time - O(n)
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Space - O(h) h = height of binary tree
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*/