Create Binary Tree From Descriptions LeetCode solution in Java

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class Solution {
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  public TreeNode createBinaryTree(int[][] descriptions) {
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    HashMap<Integer, TreeNode> map = new HashMap<>();
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    HashSet<Integer> children = new HashSet<>();
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    for (int[] info : descriptions) {
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      int parent = info[0], child = info[1];
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      boolean isLeft = info[2] == 1 ? true : false;
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      TreeNode parentNode = null;
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      TreeNode childNode = null;
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      if (map.containsKey(parent)) parentNode = map.get(parent);
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      else parentNode = new TreeNode(parent);
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      if (map.containsKey(child)) childNode = map.get(child);
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      else childNode = new TreeNode(child);
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      if (isLeft) parentNode.left = childNode;
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      else parentNode.right = childNode;
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      map.put(parent, parentNode);
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      map.put(child, childNode);
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      children.add(child);
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    }
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    TreeNode root = null;
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    for (int info[] : descriptions) {
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      if (!children.contains(info[0])) {
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        root = map.get(info[0]);
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        break;
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      }
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    }
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    return root;
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  }
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}