Create tree.cpp

Author: wlgq2

0____剑指offer/tree/33.search_tree/tree.cpp

@@ -0,0 +1,23 @@
+class Solution 
+{
+public:
+    bool verifyPostorder(vector<int>& postorder, int start, int end)
+    {
+        if (start >= end)
+            return true;
+        int root = postorder[end];
+        int index = end - 1;
+        for (;index >= start;index--)
+            if (postorder[index] < root)
+                break;
+        int less = index;
+        while (less >= start)
+            if (postorder[less--] >= root)
+                return false;
+        return verifyPostorder(postorder, start, index) && verifyPostorder(postorder, index + 1, end - 1);
+    }
+    bool verifyPostorder(vector<int>& postorder) 
+    {
+        return verifyPostorder(postorder, 0, postorder.size() - 1);
+    }
+};