Longest Consecutive Sequence

Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence.

Example 1:

Input: nums = [100,4,200,1,3,2]
Output: 4

Approach

Java

import java.util.Arrays;
public class LongestConsecutiveSequence {
    public static void main(String[] args) {
        int[] nums = { 100, 4, 200, 1, 3, 2 };
        System.out.println(longestConsecutive(nums));
    }
    // method to find the length of longest
    // consecutive sequence
    static int longestConsecutive(int[] nums) {
        if (nums.length == 0)
            return 0;
        Arrays.sort(nums);
        int cnt = 1, res = 1;
        for (int i = 1; i < nums.length; i++) {
            if (nums[i] == 1 + nums[i - 1]) {
                cnt++;
            } else if (nums[i] == nums[i - 1])
                continue;
            else {
                res = Math.max(res, cnt);
                cnt = 1;
            }
        }
        res = Math.max(res, cnt);
        return res;
    }
}

C++

#include <bits/stdc++.h>
using namespace std;
//function to find the length of longest
//consecutive sequence
int longestConsecutive(vector<int>& nums)
{
        sort(nums.begin(),nums.end());
        if(nums.size()==0)
               return 0;
        int cnt=1,res=1;
        for(int i=1;i<nums.size();i++)
        {
            if(nums[i]==1+nums[i-1])
            {
                cnt++;
            }
             else if(nums[i]==nums[i-1])
                    continue;
            else
            {
                res=max(res,cnt);
                cnt=1;
            }
                
        }
        res=max(res,cnt);
           return res; 
}
int main()
{
    vector<int> nums = {100,4,200,1,3,2};
    cout<<longestConsecutive(nums);
    return 0;
}