solves #105 in java

Author: anishLearnsToCode

Diff for: README.md

@@ -97,7 +97,7 @@
 | 102  | [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal)                                                      |                                                          [![Java](assets/java.png)](src/BinaryTreeLevelOrderTraversal.java)                                                          |                                                                                                                                   |
 | 103  | [Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal)                                        |                                                       [![Java](assets/java.png)](src/BinaryTreeZigzagLevelOrderTraversal.java)                                                       |                                                                                                                                   |
 | 104  | [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree)                                                                |                         [![Java](assets/java.png)](src/MaximumDepthOfBinaryTree.java) [![Python](assets/python.png)](python/maximum_depth_of_binary_tree.py)                         |                                                                                                                                   |
-| 105  | [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal)      |                                                                                                                                                                                      |                                                                                                                                   |
+| 105  | [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal)      |                                               [![Java](assets/java.png)](src/ConstructBinaryTreeFromPreorderAndInorderTraversal.java)                                                |                                                                                                                                   |
 | 106  | [Construct Binary Tree from Inorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal)    |                                                                                                                                                                                      |                                                                                                                                   |
 | 107  | [Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii)                                                |                 [![Java](assets/java.png)](src/BinaryTreeLevelOrderTraversalII.java) [![Python](assets/python.png)](python/binary_tree_level_order_traversal_ii.py)                  |                                                                                                                                   |
 | 108  | [Convert Sorted Array To Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree)                                    |           [![Java](assets/java.png)](src/ConvertSortedArrayToBinarySearchTree.java) [![Python](assets/python.png)](python/converted_sorted_array_to_binary_search_tree.py)           |                                                                                                                                   |

Diff for: src/ConstructBinaryTreeFromPreorderAndInorderTraversal.java

@@ -0,0 +1,34 @@
+// https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal
+// T: O(n)
+// S: O(n)
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ConstructBinaryTreeFromPreorderAndInorderTraversal {
+    int preOrderIndex = 0;
+    Map<Integer, Integer> inOrderIndices;
+
+    public TreeNode buildTree(int[] preorder, int[] inorder) {
+        inOrderIndices = buildValueToIndexMap(inorder);
+        return buildTree(preorder, inorder, 0, preorder.length);
+    }
+
+    private TreeNode buildTree(int[] preOrder, int[] inOrder, int start, int end) {
+        if (start >= end) return null;
+
+        int inOrderIndex = inOrderIndices.get(preOrder[preOrderIndex]);
+        final TreeNode root = new TreeNode(preOrder[preOrderIndex++]);
+        root.left = buildTree(preOrder, inOrder, start, inOrderIndex);
+        root.right = buildTree(preOrder, inOrder, inOrderIndex + 1, end);
+        return root;
+    }
+
+    private Map<Integer, Integer> buildValueToIndexMap(int[] array) {
+        final Map<Integer, Integer> result = new HashMap<>();
+        for (int index = 0 ; index < array.length ; index++) {
+            result.put(array[index], index);
+        }
+        return result;
+    }
+}