2problems completed

Palindrome partitioning.py

@@ -0,0 +1,31 @@
+class Solution:
+    def partition(self, s: str) -> List[List[str]]:
+        self.result=[]
+        self.helper(s,0,[])
+        return self.result
+
+    def helper(self,s,pivot,path):
+        #base case
+        if pivot==len(s):
+            self.result.append(path[:]) #copy
+            return
+        for i in range(pivot,len(s)):
+            curr_str=s[pivot:i+1]
+            if self.isPalindrome(curr_str):
+                #action
+                path.append(curr_str)
+                #recurse
+                self.helper(s,i+1,path)
+                #backtrack
+                path.pop()
+
+    def isPalindrome(self,s):
+        l=0
+        h=len(s)-1
+
+        while l<h:
+            if s[l]!=s[h]:
+                return False
+            l=l+1
+            h=h-1
+        return True

subsets.py

@@ -0,0 +1,16 @@
+class Solution:
+    def subsets(self, nums: List[int]) -> List[List[int]]:
+        self.result=[]
+        self.helper(nums,0,[])
+        return self.result
+
+    def helper(self,nums,i,path):
+        #base
+        if i==len(nums):
+            self.result.append(path)
+            return
+
+        #nochoose
+        self.helper(nums,i+1,path)
+        #choose
+        self.helper(nums,i+1,path+[nums[i]])