<p>Given an unsorted array of integers <code>nums</code>, return <em>the length of the longest consecutive elements sequence.</em></p>

<p>You must write an algorithm that runs in&nbsp;<code>O(n)</code>&nbsp;time.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [100,4,200,1,3,2]
<strong>Output:</strong> 4
<strong>Explanation:</strong> The longest consecutive elements sequence is <code>[1, 2, 3, 4]</code>. Therefore its length is 4.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [0,3,7,2,5,8,4,6,0,1]
<strong>Output:</strong> 9
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>0 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>9</sup> &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
</ul>

class Solution {
public:
    int longestConsecutive(vector<int>& nums) {
        map<int,int>m;
        for(auto it:nums)
        {
            m[it]++;

        }
        for(auto it:m)
        {
            cout<<it.first<<endl;
        }
        int count=0;
        int maxcount=0;
        int prev=INT_MIN;
        for(auto it:m)
        {
            if(prev==INT_MIN)
            {
                prev=it.first;
                count++;
                
            }
           else if((it.first - prev)!=1)
           {
            count=1;
            prev=it.first;
           }
           else if(it.first-prev==1)
           {
            count++;
            prev=it.first;
            
           }
           maxcount=max(count,maxcount);
        }
        return maxcount;
    }
};
76801