Determining if an Array Contains Duplicates

Problem

Given an array of integers, write a function that determines whether the array contains any duplicates. Your function should return true if any element appears more than once in the array, and false if every element is unique.
Example input: [1, 2, 3, 4, 5]
Example output: false
Example input: [1, 2, 3, 4, 4]
Example output: true

Solution

This solution is in C++. Our A.I. can create solutions in multiple languages.

kayakane

#include <iostream>
#include <vector>
#include <unordered_set>

using namespace std;

bool containsDuplicates(vector<int>& nums) {
    unordered_set<int> set;
    for (int i = 0; i < nums.size(); i++) {
        if (set.find(nums[i]) != set.end()) {
            return true;
        }
        set.insert(nums[i]);
    }
    return false;
}

int main() {
    vector<int> nums1 = {1, 2, 3, 4, 5};
    vector<int> nums2 = {1, 2, 3, 4, 4};
    cout << containsDuplicates(nums1) << endl;
    cout << containsDuplicates(nums2) << endl;
    return 0;
}