Given numRows, generate the first numRows of Pascal‘s triangle.

For example, given numRows = 5,
Return

[
     [1],
    [1,1],
   [1,2,1],
  [1,3,3,1],
 [1,4,6,4,1]
]

class Solution {
public:
    std::vector<std::vector<int> > generate(int numRows) {
		std::vector<int> vec;
		std::vector<std::vector<int>> res(numRows,vec);
		int triangle[100][100];
		for (int i = 0; i < numRows; i++)
		{
			triangle[i][0] = 1;
			triangle[i][i] = 1;
		}
		for (int i = 2; i < numRows; i++)
		{
			for (int j = 1; j < i + 1; j++)
			{
				triangle[i][j] = triangle[i-1][j-1] + triangle[i-1][j];
			}
		}
		for (int i = 0; i < numRows; i++)
		{
			for (int j = 0; j <= i; j++)
			{
				res[i].push_back(triangle[i][j]);
			}
		}
		return res;
    }
};

leetcode - Pascal's Triangle