题目顺序来源https://neetcode.io/practice
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Arrays & Hashing
Problem 217. Contains Duplicate
Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
Example 1:
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Input: nums = [1,2,3,1]
Output: true
Example 2:
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Input: nums = [1,2,3,4]
Output: false
Example 3:
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Input: nums = [1,1,1,3,3,4,3,2,4,2]
Output: true
Idea + Solution
1. hashset
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class Solution:
def containsDuplicate(self, nums: List[int]) -> bool:
hashset = set()
for n in nums:
if n in hashset:
return True
hashset.add(n)
return False
2. set()
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class Solution:
def containsDuplicate(self, nums: List[int]) -> bool:
if len(nums) != len(set(nums)):
return True
return False
