LeetCode-217. Contains Duplicate [C++][Java]

LeetCode-217. Contains Duplicatehttps://leetcode.com/problems/contains-duplicate/

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 <= 10^5
• -10^9 <= nums[i] <= 10^9

【C++】

class Solution {
public:
    bool containsDuplicate(vector& nums) {
        set s;
        for (int num : nums) s.insert(num);
        return s.size() < nums.size();
    }
};

class Solution {
public:
    bool containsDuplicate(vector& nums) {
        sort(nums.begin(), nums.end());
        if (nums.size() == 0) return false;
        for(int i=0; i

class Solution {
    public boolean containsDuplicate(int[] nums) {
        Set s = new HashSet<>();
        for (int num : nums) s.add(num);
        return s.size() < nums.length;
    }
}