[sangbeenmoon] WEEK 01 solutions

house-robber/sangbeenmoon.py

@@ -14,3 +14,29 @@ def rob(self, nums: List[int]) -> int:
             dp[i] = max(dp[i-2] + nums[i] , dp[i-1])
 
         return dp[len(nums) - 1]
+
+
+
+
+
+# dp[i] = max(dp[i-1], dp[i-2] + num[i])
+# TC : O(n)
+# SC : O(n)
+
+class Solution:
+    def rob(self, nums: List[int]) -> int:
+        dp = [0] * len(nums)
+
+        dp[0] = nums[0]
+
+        if len(nums) == 1:
+            return dp[0]
+
+        dp[1] = max(nums[0],nums[1])
+
+        for i in range(2, len(nums)):
+            dp[i] = max(dp[i-1], dp[i-2] + nums[i])
+
+        return max(dp)
+
+

longest-consecutive-sequence/sangbeenmoon.py

@@ -16,3 +16,36 @@ def longestConsecutive(self, nums: List[int]) -> int:
                 answer = max(answer , length)
 
         return answer
+
+
+
+# 정렬하면 쉬운데 O(n)이 필요하네 → set으로 조회를 O(1)로 → 근데 중복으로 세네 → 시작점에서만 세자
+
+# TC : O(n)
+# SC : O(n)
+
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        s = set()
+
+        for num in nums:
+            s.add(num)
+
+        ans = 0
+
+        for num in s:
+            if num - 1 in s:
+                continue
+
+            sub_ans = 1
+            next_num = num + 1
+            while next_num in s:
+                sub_ans = sub_ans + 1
+                next_num = next_num + 1
+            ans = max(ans, sub_ans)
+
+        return ans
+
+
+
+

top-k-frequent-elements/sangbeenmoon.py

@@ -29,3 +29,30 @@ def topKFrequent(self, nums: List[int], k: int) -> List[int]:
 
 
 
+# TC: O(nlogn)
+# SC: O(n)
+
+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        count_map = {}
+
+        for num in nums:
+            if num in count_map:
+                count_map[num] = count_map[num] + 1
+            else:
+                count_map[num] = 1
+
+        tuple_list = []
+
+        for item in count_map.items():
+            tuple_list.append(item)
+
+        tuple_list.sort(key=lambda x: x[1], reverse=True)
+
+        answer = []
+        for i in range(k):
+            answer.append(tuple_list[i][0])
+
+
+        return answer
+