LeetCode 217 Contain Duplicates

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.

Diffculty
Easy

Similar Problems

[LeetCode 219] Contain Duplicates II Easy [LeetCode 220] Contain Duplicates III Medium

Analysis

Solutions

class Solution {
  public:
    bool containsDuplicate(vector<int>& nums) {
        return set<int>(nums.begin(), nums.end()).size() < nums.size();
    }
};

// sort, then compare neighbor elements
class Solution {
public:
    bool containsDuplicate(std::vector<int>& nums) {
        std::sort(nums.begin(), nums.end());
        for (int i = 1; i < nums.size(); ++i)
            if (nums[i] == nums[i - 1])
                return true;
        return false;
    }
};

Reference