<p>You are given an integer <code>n</code>.</p>

<p>Each number from <code>1</code> to <code>n</code> is grouped according to the sum of its digits.</p>

<p>Return <em>the number of groups that have the largest size</em>.</p>

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

<pre>
<strong>Input:</strong> n = 13
<strong>Output:</strong> 4
<strong>Explanation:</strong> There are 9 groups in total, they are grouped according sum of its digits of numbers from 1 to 13:
[1,10], [2,11], [3,12], [4,13], [5], [6], [7], [8], [9].
There are 4 groups with largest size.
</pre>

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

<pre>
<strong>Input:</strong> n = 2
<strong>Output:</strong> 2
<strong>Explanation:</strong> There are 2 groups [1], [2] of size 1.
</pre>

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

<ul>
	<li><code>1 &lt;= n &lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
public:
    int countLargestGroup(int n) {
        map<int,int> groups;
        for(int i=1;i<=n;i++){
            string num = to_string(i);
            int numTotal = 0;
            for (char c:num){
                string s{c};
                numTotal += std::stoi(s);
            }
            
            if(groups.count(numTotal) == 1){
                groups.at(numTotal) = groups.at(numTotal) + 1;
            } else {
                groups.insert({numTotal,1});
            }
        }

        int num_max = 0;
        int max_groups = 0;
        for (auto group:groups){
            if (group.second > num_max){
                num_max = group.second;
                max_groups = 1;
            } else if (group.second == num_max){
                max_groups ++;
            }
        }

        return max_groups;
    }
};
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