<p>Given an integer <code>numRows</code>, return the first numRows of <strong>Pascal&#39;s triangle</strong>.</p>

<p>In <strong>Pascal&#39;s triangle</strong>, each number is the sum of the two numbers directly above it as shown:</p>
<img alt="" src="https://upload.wikimedia.org/wikipedia/commons/0/0d/PascalTriangleAnimated2.gif" style="height:240px; width:260px" />
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> numRows = 5
<strong>Output:</strong> [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> numRows = 1
<strong>Output:</strong> [[1]]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= numRows &lt;= 30</code></li>
</ul>

class Solution {
public:
    long long int fact(int k)
    {
        if(k==0)
            return 1;
         long long int ans=1;
        while(k>0)
        {
            ans*=k;
            k-=1;
        }
        return ans;
    }

    int comb(int n, int r)
    {
        int z=min(r,n-r);
        long long int numerator=1,denominator;
        for(int i=0;i<z;i++)
        {
            numerator*=n;
            n-=1;
        }
        denominator=fact(z);
        int ans=numerator/denominator;
        return ans;
    }

    vector<int> helper(int num)
    {
        int element;vector<int> row;
        for(int i=0;i<num;i++)
        {
            element=comb(num,i);
            row.push_back(element);
        }
        row.push_back(1);
        return row;
    }

    vector<vector<int>> generate(int numRows) 
    {
        vector<vector<int>> result;vector<int> item;
        for(int i=0;i<numRows;i++)
        {
            item=helper(i);
            result.push_back(item);
        }

        return result;
        
    }
};
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