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Add solution 105.

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src/Algorithms/0105.construct-binary-tree-from-preorder-and-inorder-traversal
- construct-binary-tree-from-preorder-and-inorder-traversal.php

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	`1`	`+/**`
	`2`	`+ * Definition for a binary tree node.`
	`3`	`+ * class TreeNode {`
	`4`	`+ * public $val = null;`
	`5`	`+ * public $left = null;`
	`6`	`+ * public $right = null;`
	`7`	`+ * function __construct($value) { $this->val = $value; }`
	`8`	`+ * }`
	`9`	`+ */`
	`10`	`+class Solution {`
	`11`	`+`
	`12`	`+ /**`
	`13`	`+ * @param Integer[] $preorder`
	`14`	`+ * @param Integer[] $inorder`
	`15`	`+ * @return TreeNode`
	`16`	`+ */`
	`17`	`+ function buildTree($preorder, $inorder) {`
	`18`	`+ $map = [];`
	`19`	`+ for ($i = 0; $i < count($inorder); $i++) {`
	`20`	`+ $map[$inorder[$i]] = $i;`
	`21`	`+ }`
	`22`	`+ return self::helper($preorder, $inorder, $map, 0, 0, count($inorder) - 1);`
	`23`	`+ }`
	`24`	`+ function helper($preorder, $inorder, $map, $index, $start, $end) {`
	`25`	`+ if ($index >= count($preorder) \|\| $start > $end) {`
	`26`	`+ return null;`
	`27`	`+ }`
	`28`	`+ $root = new TreeNode($preorder[$index]);`
	`29`	`+ $k = $map[$root->val];`
	`30`	`+ $root->left = self::helper($preorder, $inorder, $map, $index + 1, $start, $k - 1);`
	`31`	`+ $root->right = self::helper($preorder, $inorder, $map, $index + 1 + $k - $start, $k + 1, $end);`
	`32`	`+ return $root;`
	`33`	`+ }`
	`34`	`+}`

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