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
Solution:
class Solution {
public:
bool containsDuplicate(vector<int>& nums) {
unordered_set<int> s;
for(auto i : nums)
{
if(s.find(i) != s.end())
return true;
s.insert(i);
}
return false;
}
};