create 2002 in py

Author: Mohammed785

python/2002-maximum-product-of-the-length of-2-palindromic-subsequences.py

@@ -0,0 +1,30 @@
+"""
+Time Complexity: O(2^N)
+Space Complexity: O(2^N)
+"""
+class Solution:
+    def maxProduct(self, s):
+        n = len(s)
+        
+        first, last = [0]*(1<<n), [0]*(1<<n)
+        
+        for i in range(n):
+            for j in range(1<<i, 1<<(i+1)):
+                first[j] = i
+
+        for i in range(n):
+            for j in range(1<<i, 1<<n, 1<<(i+1)):
+                last[j] = i
+        
+        @lru_cache(None)
+        def dp(m):
+            if m & (m-1) == 0: return m != 0
+            l, f = last[m], first[m]
+            lb, fb = 1<<l, 1<<f
+            return max(dp(m-lb), dp(m-fb), dp(m-lb-fb) + (s[l] == s[f]) * 2)
+       
+        ans = 0
+        for m in range(1, 1<<n):
+            ans = max(ans, dp(m)*dp((1<<n) - 1 - m))
+            
+        return ans