<p>There are <code>n</code> persons on a social media website. You are given an integer array <code>ages</code> where <code>ages[i]</code> is the age of the <code>i<sup>th</sup></code> person.</p>

<p>A Person <code>x</code> will not send a friend request to a person <code>y</code> (<code>x != y</code>) if any of the following conditions is true:</p>

<ul>
	<li><code>age[y] &lt;= 0.5 * age[x] + 7</code></li>
	<li><code>age[y] &gt; age[x]</code></li>
	<li><code>age[y] &gt; 100 &amp;&amp; age[x] &lt; 100</code></li>
</ul>

<p>Otherwise, <code>x</code> will send a friend request to <code>y</code>.</p>

<p>Note that if <code>x</code> sends a request to <code>y</code>, <code>y</code> will not necessarily send a request to <code>x</code>. Also, a person will not send a friend request to themself.</p>

<p>Return <em>the total number of friend requests made</em>.</p>

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

<pre>
<strong>Input:</strong> ages = [16,16]
<strong>Output:</strong> 2
<strong>Explanation:</strong> 2 people friend request each other.
</pre>

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

<pre>
<strong>Input:</strong> ages = [16,17,18]
<strong>Output:</strong> 2
<strong>Explanation:</strong> Friend requests are made 17 -&gt; 16, 18 -&gt; 17.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> ages = [20,30,100,110,120]
<strong>Output:</strong> 3
<strong>Explanation:</strong> Friend requests are made 110 -&gt; 100, 120 -&gt; 110, 120 -&gt; 100.
</pre>

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

<ul>
	<li><code>n == ages.length</code></li>
	<li><code>1 &lt;= n &lt;= 2 * 10<sup>4</sup></code></li>
	<li><code>1 &lt;= ages[i] &lt;= 120</code></li>
</ul>

class Solution {
public:
    bool check(int x,int y){
        if(y>x)
            return false;
        if(y<=0.5*x+7)
            return false;
        if(y>100 && x<100)
            return false;
        
        return true;
    }
    int numFriendRequests(vector<int>& ages2) {
        int ans=0;
        sort(ages2.begin(),ages2.end());

        for(int i=ages2.size()-1;i>=1;i--)
        {
            cout<<"\nSolving for"<<ages2[i]<<endl;
            int start=0;
            int end=i-1;
            int mid=0;
            int validIndex=i;
            while(start<=end)
            {
                mid=start+(end-start)/2;
                cout<<"checking"<<ages2[mid]<<endl;
                if(check(ages2[i],ages2[mid]))
                {
                    validIndex=mid;
                    end=mid-1;
                    //cout << "for:" << ages2[i] << " " << ages2[mid] << " ";
                }
                else
                {
                    start=mid+1;
                }
            }
            int temp=i-validIndex;
            int c=0;
            int j=i;
            while(j>=0 && ages2[j]==ages2[i]){
                c++;
                j--;
            }
            ans+=temp*c;
            i=i-c+1;
            // cout << "\n";
            //  cout<<"ValidIndex"<<ages2[validIndex]<<endl;
            // int temp=(i-validIndex+mp[ages2[i]]-1)*mp[ages2[i]];
            // cout<<temp<<endl;
            // ans+=temp;
        }
       return ans;
    }
};
41000