Contains Duplicate
Problem
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:
Input: nums = [1,2,3,1]
Output: true
Example 2:
Input: nums = [1,2,3,4]
Output: false
Example 3:
Input: nums = [1,1,1,3,3,4,3,2,4,2]
Output: true
Constraints:
1 <= nums.length <= 105-109 <= nums[i] <= 109
Solution
- HashMap
- Time: O(n)
- Space: O(n)
class Solution(object):
def containsDuplicate(self, nums):
"""
:type nums: List[int]
:rtype: bool
"""
hashset = set()
for n in nums:
if n in hashset:
return True
hashset.add(n)
return False