[SAM] Week 12 solutions

jump-game/samthekorean.py

@@ -0,0 +1,10 @@
+# TC : O(n)
+# SC : O(1)
+class Solution:
+    def canJump(self, nums):
+        reachable = 0
+        for i in range(len(nums)):
+            if i > reachable:
+                return False
+            reachable = max(reachable, i + nums[i])
+        return True

longest-common-subsequence/samthekorean.py

@@ -0,0 +1,13 @@
+# m is the length of text1 and n is the length of text2
+# TC : O(m * n)
+# SC : O(m * n)
+class Solution:
+    def longestCommonSubsequence(self, text1: str, text2: str) -> int:
+        dp = [[0] * (len(text2) + 1) for _ in range(len(text1) + 1)]
+        for r in range(1, len(text1) + 1):
+            for c in range(1, len(text2) + 1):
+                if text1[r - 1] == text2[c - 1]:
+                    dp[r][c] = 1 + dp[r - 1][c - 1]
+                else:
+                    dp[r][c] = max(dp[r - 1][c], dp[r][c - 1])
+        return dp[-1][-1]

longest-increasing-subsequence/samthekorean.py

@@ -0,0 +1,10 @@
+# TC : O(n^2)
+# SC : O(n)
+class Solution:
+    def lengthOfLIS(self, nums: List[int]) -> int:
+        dp = [1] * len(nums)
+        for cur in range(1, len(nums)):
+            for pre in range(cur):
+                if nums[pre] < nums[cur]:
+                    dp[cur] = max(1 + dp[pre], dp[cur])
+        return max(dp)

maximum-subarray/samthekorean.py

@@ -0,0 +1,15 @@
+# TC : O(n)
+# SC : O(1)
+class Solution:
+    def maxSubArray(self, nums: List[int]) -> int:
+        res = nums[0]
+        total = 0
+
+        for n in nums:
+            if total < 0:
+                total = 0
+
+            total += n
+            res = max(res, total)
+
+        return res

unique-paths/samthekorean.py

@@ -0,0 +1,5 @@
+# TC : O(n)
+# SC : O(1)
+class Solution:
+    def uniquePaths(self, m: int, n: int) -> int:
+        return math.comb(m + n - 2, n - 1)