[prograsshopper] Week 1 Solutions

contains-duplicate/prograsshopper.py

@@ -0,0 +1,3 @@
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        return len(set(nums)) != len(nums)

top-k-frequent-elements/prograsshopper.py

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+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        from collections import defaultdict
+        frequent_dict = defaultdict(int)
+        for num in nums:
+            frequent_dict[num] += 1
+        sorted_dict = dict(sorted(frequent_dict.items(), key=operator.itemgetter(1), reverse=True))
+        return list(sorted_dict)[:k]

two-sum/prograsshopper.py

@@ -0,0 +1,10 @@
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        index_dict = {elem: idx for idx, elem in enumerate(nums)}
+        result = []
+        for idx, num in enumerate(nums):
+            remain = index_dict.get(target-num, None)
+            if remain and idx != remain:
+                result = [idx, remain]
+                break
+        return result