feat: [Week 06-4] solve longest-increasing-subsequence

Author: Chaedie

longest-increasing-subsequence/Chaedie.py

@@ -0,0 +1,44 @@
+"""
+Solution: 1) DFS Brute Force -> TLE
+Time: O(2^n * nlogn)
+"""
+
+
+class Solution:
+    def lengthOfLIS(self, nums: List[int]) -> int:
+
+        sub = []
+        max_len = 0
+
+        def dfs(i, length):
+            nonlocal max_len
+            if i == len(nums):
+                if sub == sorted(list(set(sub))):
+                    max_len = max(len(sub), max_len)
+                return
+
+            dfs(i + 1, length)
+            sub.append(nums[i])
+            dfs(i + 1, length)
+            sub.pop()
+
+        dfs(0, 0)
+        return max_len
+
+
+"""
+풀이를 보고 적었으며, 완벽히 이해 되지는 않습니다.
+Time: O(n^2)
+Space: O(n)
+"""
+
+
+class Solution:
+    def lengthOfLIS(self, nums: List[int]) -> int:
+        LIS = [1] * len(nums)
+
+        for i in range(len(nums) - 1, -1, -1):
+            for j in range(i + 1, len(nums)):
+                if nums[i] < nums[j]:
+                    LIS[i] = max(LIS[i], 1 + LIS[j])
+        return max(LIS)