Pascal's Triangle

class Solution {
public:
    vector<vector<int> > generate(int numRows) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<vector<int> > result;
        if(numRows<=0)
        return result;
        vector<int> temp;
        temp.push_back(1);
        result.push_back(temp);
        for(int i = 2;i<=numRows;i++)
        {
            temp.clear();
            temp.push_back(1);
            for(int j = 1;j<i-1;j++)
            {
                temp.push_back(result[i-2][j-1]+result[i-2][j]);
            }
            temp.push_back(1);
            result.push_back(temp);
        }
        return result;
    }
};