[LeetCode] Construct Binary Tree from Preorder and Inorder Traversal

Given preorder and inorder traversal of a tree, construct the binary tree.

Note:

You may assume that duplicates do not exist in the tree.

/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public TreeNode buildTree(int[] preorder, int[] inorder) {
return build(inorder, 0, inorder.length - 1, preorder, 0, preorder.length - 1);
}

public TreeNode build(int[] inorder, int lo1, int hi1,
int[] preorder, int lo2, int hi2) {
if (lo2 > hi2) return null;

int index = getIndex(inorder, preorder[lo2]);

TreeNode root = new TreeNode(preorder[lo2]);
root.left = build(inorder, lo1, index - 1, preorder, lo2 + 1, lo2 + 1 + ((index - 1) - lo1));
root.right = build(inorder, index + 1, hi1, preorder,
lo2 + 1 + ((index - 1) - lo1) + 1, lo2 + 1 + ((index - 1) - lo1) + 1 + (hi1 - (index + 1)));

return root;
}

public int getIndex(int[] array, int val) {
for (int i = 0; i < array.length; i++) {
if (array[i] == val) return i;
}

return -1;
}
}