[daiyongg-kim] WEEK 01 solutions

contains-duplicate/daiyongg-kim.py

@@ -0,0 +1,10 @@
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        my_set = set()
+
+        for num in nums:
+            if num in my_set:
+                return True
+            my_set.add(num)
+        return False
+

longest-consecutive-sequence/daiyongg-kim.py

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+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        my_set = set(nums)
+        longest = 0
+        length = 1
+        for num in my_set:
+            if num - 1 not in my_set:
+                length = 1
+                while num + length in my_set:
+                    length += 1
+                longest = max (longest, length)
+
+        return longest

top-k-frequent-elements/daiyongg-kim.py

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+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        counts = Counter(nums)
+
+        items = counts.items()
+
+        sort_by_value = sorted(
+            items,
+            key=lambda item: item[1],
+            reverse = True
+        )
+        result = []
+        for i in range(k):
+            result.append(sort_by_value[i][0])
+        return result
+

two-sum/daiyongg-kim.py

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+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        hash_map = {}
+        for i, num in enumerate(nums):
+            current = target - num
+            if current in hash_map:
+                return [hash_map[current], i]
+            hash_map[num] = i
+        return []
+