Number of Longest Increasing Subsequence

python/leetcode/Number of Longest Increasing Subsequence.py

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+"""
+Number of Longest Increasing Subsequence
+"""
+from typing import List
+
+
+class Solution:
+    def findNumberOfLIS(self, nums: List[int]) -> int:
+        lis = [1] * len(nums)
+        ct = [0] * len(nums)
+
+        res = 0
+        max_len = 1
+        for i in range(len(nums) - 1, -1, -1):
+
+            tmp = 0
+            tmp_ct = 1
+            for j in range(i + 1, len(nums)):
+                if nums[i] < nums[j]:
+                    if lis[j] > tmp:
+                        tmp = lis[j]
+                        tmp_ct = ct[j]
+                    elif lis[j] == tmp:
+                        tmp_ct += ct[j]
+
+            lis[i] += tmp
+            ct[i] = tmp_ct
+
+            if max_len < lis[i]:
+                max_len = lis[i]
+                res = ct[i]
+            elif max_len == lis[i]:
+                res += ct[i]
+
+        return res
+
+
+if __name__ == "__main__":
+    obj = Solution()
+
+    nums = [1, 3, 5, 4, 7]
+    assert obj.findNumberOfLIS(nums) == 2
+
+    nums = [1, 2, 4, 3, 5, 4, 7, 2]
+    assert obj.findNumberOfLIS(nums) == 3