Create Sunny.md

sunny-ljc · web-flow · commit 8879d53e1675 · 2018-12-07T17:31:42.000-05:00
diff --git a/2018.12.08-leetcode105/Sunny.md b/2018.12.08-leetcode105/Sunny.md
@@ -0,0 +1,30 @@
+```java
+class Solution {
+
+    private int i = 0;
+    
+    public TreeNode buildTree(int[] preorder, int[] inorder) {
+        if (preorder == null || preorder.length == 0)
+            return null;
+        int val = preorder[i];
+        int index = inorder.length - 1;
+        for (; index >= 0; index--) {
+            if (inorder[index] == val) {
+                break;
+            }
+        }
+        if (index >= 0) {
+            TreeNode node = new TreeNode(val);
+            i++;
+            if (inorder.length > 1 && i < preorder.length) {
+                node.left = buildTree(preorder, Arrays.copyOfRange(inorder, 0, index));
+                if (i < preorder.length) {
+                    node.right = buildTree(preorder, Arrays.copyOfRange(inorder, index+1, inorder.length));
+                }
+            }
+            return node;
+        }
+        return null;
+    }
+}
+```
