Time: 163 ms (92.29%) | Memory: 29.7 MB (93.66%) - LeetSync

Author: joshua-dierickse-alt

4027-number-of-stable-subsequences/number-of-stable-subsequences.py

@@ -0,0 +1,22 @@
+class Solution:
+    def countStableSubsequences(self, nums: List[int]) -> int:
+        e1 = 0
+        e2 = 0
+        o1 = 0
+        o2 = 0
+
+        mod = 10 ** 9 + 7
+
+        for num in nums:
+            if num % 2 == 0:
+                e2 += e1
+                e1 += 1 + o1 + o2
+                e2 %= mod
+                e1 %= mod
+            else:
+                o2 += o1
+                o1 += 1 + e1 + e2
+                o2 %= mod
+                o1 %= mod
+        
+        return (e1 + e2 + o1 + o2) % mod