<p>Given an integer array <code>arr</code> and an integer <code>k</code>, modify the array by repeating it <code>k</code> times.</p>

<p>For example, if <code>arr = [1, 2]</code> and <code>k = 3 </code>then the modified array will be <code>[1, 2, 1, 2, 1, 2]</code>.</p>

<p>Return the maximum sub-array sum in the modified array. Note that the length of the sub-array can be <code>0</code> and its sum in that case is <code>0</code>.</p>

<p>As the answer can be very large, return the answer <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p>

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

<pre>
<strong>Input:</strong> arr = [1,2], k = 3
<strong>Output:</strong> 9
</pre>

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

<pre>
<strong>Input:</strong> arr = [1,-2,1], k = 5
<strong>Output:</strong> 2
</pre>

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

<pre>
<strong>Input:</strong> arr = [-1,-2], k = 7
<strong>Output:</strong> 0
</pre>

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

<ul>
	<li><code>1 &lt;= arr.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= k &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>4</sup> &lt;= arr[i] &lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
public:
    int kConcatenationMaxSum(vector<int>& arr, int k) {
        int n = arr.size();
        int MOD = 1e9 + 7;
        int totalSum = 0;
        for (int i = 0; i < n; i++){
            totalSum += arr[i];
            if(k>1)
            arr.push_back(arr[i]);
        }
        n= arr.size();
        int start = 0;
        long long maxi = 0;
        int sum = 0;
        for (int i = 0; i < n; i++) {
            if (sum >= 0) {
                sum += arr[i];
                if (sum > maxi) {
                    maxi = sum;
                }
            }
            if (sum < 0) {
                sum = 0;
            }
        }
        cout<<maxi;
        if(totalSum>0 && k>1) 
         return (maxi+(long long)(k-2)*totalSum)%MOD;
        else 
         return maxi;
    }
    // Find all the Sub array sum.
    // Check if repeating that over the entire array K times is larger than 0.
    // Return the maximum possible
    // If '<' 0 return 0
};
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