0217-Contains-Duplicate.py

'''
Given an array of integers, find if the array contains any duplicates.

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Example 1:
Input: [1,2,3,1]
Output: true

Example 2:
Input: [1,2,3,4]
Output: false

Example 3:
Input: [1,1,1,3,3,4,3,2,4,2]
Output: true
'''

from typing import List

# Using Hash Set

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

# Using Hash Map

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        d = {}
        for num in nums:
            if num in d:
                return True
            d[num] = 1
        return False

# Check Custom Input

s = Solution()
answer = s.containsDuplicate([2, 2, 1, 3]) # True
print(answer)