Backtracking-2 completed

Problem-72 Subsets.py

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+# 78. Subsets
+
+# Time Complexity: O(2^n)
+# Space Complexity: O(n)
+
+class Solution:
+    def subsets(self, nums: List[int]) -> List[List[int]]:
+        result = [[]]
+        if not nums:
+            return result
+
+        self.helper(nums, 0, [], result)
+        return result
+
+    def helper(self, nums, pivot, path, result):
+        # Base
+        if pivot == len(nums):
+            return
+
+        #
+        for i in range(pivot, len(nums)):
+            path.append(nums[i])
+            self.helper(nums, i+1, path, result)
+            result.append(list(path))
+            path.pop()
+        return

Problem-73 Palindrome Partitioning.py

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+# 131. Palindrome Partitioning
+
+# Time Complexity: O(n*2^n)
+# Space Complexity: O(n)
+
+class Solution:
+    def partition(self, s: str) -> List[List[str]]:
+        result = list()
+
+        self.helper(s, 0, list(), result)
+        return result
+
+    def helper(self, s, idx, path, result):
+        # Base
+        if idx == len(s):
+            result.append(list(path))
+            return
+
+        # Logic
+        for i in range(idx, len(s)):
+            if self.isPalindrome(s, idx, i):
+                path.append(s[idx:i+1])
+                self.helper(s, i+1, path, result)
+                path.pop()
+
+    def isPalindrome(self, s, l, r):
+        while l < r:
+            if s[l] != s[r]:
+                return False
+            l += 1
+            r -= 1
+        return True