[croucs] WEEK 1

contains-duplicate/heypaprika.py

@@ -0,0 +1,11 @@
+# Big-O 예상 : O(n*k)
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        num_dict = {}
+        for num in nums:
+            if num in num_dict:
+                return True
+            else:
+                num_dict[num] = 1
+        return False
+

house-robber/heypaprika.py

@@ -0,0 +1,19 @@
+# Big-O 예상 : O(n)
+class Solution:
+    def rob(self, nums: List[int]) -> int:
+        a = [0] * len(nums)
+
+        if len(nums) == 1:
+            return nums[0]
+        elif len(nums) == 2:
+            return max(nums[0], nums[1])
+
+        a[0] = nums[0]
+        a[1] = nums[1]
+        a[2] = max(a[0] + nums[2], a[1])
+
+        for i in range(3, len(nums)):
+            a[i] = max(a[i-3], a[i-2]) + nums[i]
+
+        return max(a)
+

longest-consecutive-sequence/heypaprika.py

@@ -0,0 +1,22 @@
+# Big-O 예상 : O(nlog(n))
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        nums = sorted(list(set(nums)))
+        if len(nums) == 0:
+            return 0
+        elif len(nums) == 1:
+            return 1
+        cur_long = 1
+        longest = 1
+        for i, num in enumerate(nums):
+            if i == 0:
+                continue
+            else:
+                if nums[i-1] + 1 == nums[i]:
+                    cur_long += 1
+                    if longest < cur_long:
+                        longest = cur_long
+                else:
+                    cur_long = 1
+        return longest
+

top-k-frequent-elements/heypaprika.py

@@ -0,0 +1,16 @@
+# Big-O 예상 : O(nlog(n))
+import heapq
+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+
+        num_dict = {}
+        for num in nums:
+            num_dict[num] = num_dict.get(num, 0) + 1
+        heap = []
+        for k_, v in num_dict.items():
+            heapq.heappush(heap, [-v, k_])
+        ans = []
+        for i in range(k):
+            ans.append(heapq.heappop(heap)[1])
+        return ans
+

valid-palindrome/heypaprika.py

@@ -0,0 +1,15 @@
+# Big-O 예상 : O(n)
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        s = "".join(s.lower().split(" "))
+        new_s = ""
+        for item in s:
+            if (ord("a") <= ord(item) <= ord("z")) or (ord("0") <= ord(item) <= ord("9")):
+                new_s += item
+        output = True
+        for i in range(len(new_s) // 2):
+            if new_s[i] != new_s[-i-1]:
+                output = False
+                break
+        return output
+