Add sorts for python3

sorts/pancake_sort.py

@@ -0,0 +1,16 @@
+# Pancake sort algorithm 
+# Only can reverse array from 0 to i
+
+def pancakesort(arr):
+    cur = len(arr)
+    while cur > 1:
+        # Find the maximum number in arr
+        mi = arr.index(max(arr[0:cur]))
+        # Reverse from 0 to mi 
+        arr = arr[mi::-1] + arr[mi+1:len(arr)]
+        # Reverse whole list 
+        arr = arr[cur-1::-1] + arr[cur:len(arr)]
+        cur -= 1
+    return arr
+
+print(pancakesort([0,10,15,3,2,9,14,13]))

sorts/tree_sort.py

@@ -0,0 +1,45 @@
+# Tree_sort algorithm
+# Build a BST and in order traverse.
+
+class node():
+    # BST data structure
+    def __init__(self, val):
+        self.val = val
+        self.left = None 
+        self.right = None 
+    
+    def insert(self,val):
+        if self.val:
+            if val < self.val:
+                if self.left == None:
+                    self.left = node(val)
+                else:
+                    self.left.insert(val)
+            elif val > self.val:
+                if self.right == None:
+                    self.right = node(val)
+                else:
+                    self.right.insert(val)
+        else:
+            self.val = val
+
+def inorder(root, res):
+    # Recursive travesal 
+    if root:
+        inorder(root.left,res)
+        res.append(root.val)
+        inorder(root.right,res)
+
+def treesort(arr):
+    # Build BST
+    if len(arr) == 0:
+        return arr
+    root = node(arr[0])
+    for i in range(1,len(arr)):
+        root.insert(arr[i])
+    # Traverse BST in order. 
+    res = []
+    inorder(root,res)
+    return res
+
+print(treesort([10,1,3,2,9,14,13]))