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<?php |
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declare(strict_types=1); |
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namespace leetcode; |
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use leetcode\util\TreeNode; |
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class AverageOfLevelsInBinaryTree |
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{ |
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public static function averageOfLevels(TreeNode $root): array |
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{ |
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if (!$root) { |
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return []; |
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} |
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$ans = $queue = []; |
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$queue = [$root]; |
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while ($queue) { |
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[$curr, $n] = [[], count($queue)]; |
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for ($i = 0; $i < $n; $i++) { |
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$node = array_shift($queue); |
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if ($node instanceof TreeNode && $node->val) { |
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array_push($curr, $node->val); |
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if ($node->left && $node->left->val) { |
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array_push($queue, $node->left); |
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} |
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if ($node->right && $node->right->val) { |
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array_push($queue, $node->right); |
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} |
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} |
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} |
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$val = round(array_sum($curr) / $n, 2); |
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array_push($ans, $val); |
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} |
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return $ans; |
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} |
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public static function averageOfLevels2(TreeNode $root): array |
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{ |
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if (!$root) { |
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return []; |
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} |
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$ans = []; |
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self::dfs($root, 0, $ans); |
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return $ans; |
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} |
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private static function dfs(?TreeNode $node, int $depth, array & $ans): void |
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{ |
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if ($node instanceof TreeNode && $node->val) { |
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if ($depth === count($ans)) { |
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array_push($ans, round($node->val, 2)); |
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} else { |
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$curr = [$ans[$depth], $node->val]; |
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$ans[$depth] = round(array_sum($curr) / count($curr), 2); |
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} |
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self::dfs($node->left, $depth + 1, $ans); |
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self::dfs($node->right, $depth + 1, $ans); |
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} |
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} |
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} |
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imajinyun /
leetcode-php
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