<p>A conveyor belt has packages that must be shipped from one port to another within <code>days</code> days.</p>

<p>The <code>i<sup>th</sup></code> package on the conveyor belt has a weight of <code>weights[i]</code>. Each day, we load the ship with packages on the conveyor belt (in the order given by <code>weights</code>). We may not load more weight than the maximum weight capacity of the ship.</p>

<p>Return the least weight capacity of the ship that will result in all the packages on the conveyor belt being shipped within <code>days</code> days.</p>

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

<pre>
<strong>Input:</strong> weights = [1,2,3,4,5,6,7,8,9,10], days = 5
<strong>Output:</strong> 15
<strong>Explanation:</strong> A ship capacity of 15 is the minimum to ship all the packages in 5 days like this:
1st day: 1, 2, 3, 4, 5
2nd day: 6, 7
3rd day: 8
4th day: 9
5th day: 10

Note that the cargo must be shipped in the order given, so using a ship of capacity 14 and splitting the packages into parts like (2, 3, 4, 5), (1, 6, 7), (8), (9), (10) is not allowed.
</pre>

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

<pre>
<strong>Input:</strong> weights = [3,2,2,4,1,4], days = 3
<strong>Output:</strong> 6
<strong>Explanation:</strong> A ship capacity of 6 is the minimum to ship all the packages in 3 days like this:
1st day: 3, 2
2nd day: 2, 4
3rd day: 1, 4
</pre>

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

<pre>
<strong>Input:</strong> weights = [1,2,3,1,1], days = 4
<strong>Output:</strong> 3
<strong>Explanation:</strong>
1st day: 1
2nd day: 2
3rd day: 3
4th day: 1, 1
</pre>

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

<ul>
	<li><code>1 &lt;= days &lt;= weights.length &lt;= 5 * 10<sup>4</sup></code></li>
	<li><code>1 &lt;= weights[i] &lt;= 500</code></li>
</ul>

class Solution {
public:
        int maxday(vector<int> weights){
            int maxi= 0;
            for(auto i:weights){
                if(i>maxi){
                    maxi=i;
                }
            }
            return maxi;

        }
        int sumofdays(vector<int> num ){
            int sum= 0;
            for(auto i: num){
                sum+= i;
            }
            return sum;

        }

        int capacityfinder(vector<int>& weights, int capacity){
             int days = 1;  // Start with 1 day
        int currentLoad = 0;

        for (auto weight : weights) {
            if (currentLoad + weight > capacity) {
                // If adding the current package exceeds the capacity, start a new day
                days++;
                currentLoad = 0;
            }
            currentLoad += weight;
        }

        return days;
        }


   // Function to find the minimum ship capacity within given days
    int shipWithinDays(vector<int>& weights, int days) {
        // Minimum capacity should be the max weight (to ship the heaviest package in one day)
        int minweight = maxday(weights);
        // Maximum capacity is the total sum of weights (i.e., ship everything in one day)
        int maxweightreq = sumofdays(weights);

        // Binary search for the optimal capacity
        int left = minweight, right = maxweightreq;
        while (left < right) {
            int mid = left + (right - left) / 2;
            int daysreq = capacityfinder(weights, mid);

            if (daysreq > days) {
                // If more days are required, increase the capacity
                left = mid + 1;
            } else {
                // If the days required are less or equal, try to minimize the capacity
                right = mid;
            }
        }

        return left;
    }
};
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