[8804who] WEEK 01 solutions

contains-duplicate/8804who.py

@@ -0,0 +1,4 @@
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        return len(set(nums)) != len(nums)
+

house-robber/8804who.py

@@ -0,0 +1,14 @@
+class Solution:
+    def rob(self, nums: List[int]) -> int:
+        if len(nums) == 1:
+            return nums[0]
+        elif len(nums) == 2:
+            return max(nums)
+        else:
+            nums = [0] + nums
+            dp = [0 for _ in range(len(nums))]
+            dp[1] = nums[1]
+            for i in range(1, len(nums)):
+                dp[i] = max(dp[i-2]+nums[i], dp[i-1])
+            return dp[-1]
+

longest-consecutive-sequence/8804who.py

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+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        num_set = set(nums)
+        answer = 0
+        while num_set:
+            num = num_set.pop()
+            l, r = 1, 1
+
+            while num - l in num_set:
+                num_set.remove(num-l)
+                l += 1
+
+            while num + r in num_set:
+                num_set.remove(num+r)
+                r += 1
+
+            answer = max(answer, l+r-1)
+        return answer
+

top-k-frequent-elements/8804who.py

@@ -0,0 +1,11 @@
+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        num_list = {}
+        for num in nums:
+            if num not in num_list:
+                num_list[num] = 1
+            else:
+                num_list[num] += 1
+
+        return [n[1] for n in sorted([[num_list[key], key] for key in num_list.keys()], reverse=True)[:k]]
+

two-sum/8804who.py

@@ -0,0 +1,8 @@
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        num_list = {}
+        for i in range(len(nums)):
+            if target-nums[i] in num_list:
+                return [num_list[target-nums[i]], i]
+            num_list[nums[i]] = i
+