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java: add «2196. Create Binary Tree From Descriptions»

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Signed-off-by: Matej Focko <me@mfocko.xyz>
This commit is contained in:
Matej Focko 2024-07-15 23:54:14 +02:00
parent a718efd3d8
commit be27f896dc
Signed by: mfocko
SSH key fingerprint: SHA256:icm0fIOSJUpy5+1x23sfr+hLtF9UhY8VpMC7H4WFJP8
1 changed files with 31 additions and 0 deletions
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java/create-binary-tree-from-descriptions.java Normal file
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class Solution {
public TreeNode createBinaryTree(int[][] descriptions) {
Map<Integer, TreeNode> nodes = new HashMap<>();
Set<Integer> hasParent = new HashSet<>();
for (int[] description : descriptions) {
int parent = description[0];
int value = description[1];
boolean isLeft = description[2] == 1;
var parentNode = nodes.computeIfAbsent(parent, k -> new TreeNode(k));
var node = nodes.computeIfAbsent(value, k -> new TreeNode(k));
if (isLeft) {
parentNode.left = node;
} else {
parentNode.right = node;
}
hasParent.add(value);
}
for (var node : nodes.values()) {
if (!hasParent.contains(node.val)) {
return node;
}
}
return null;
}
}