[leetcode]Pascal's Triangle

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]
]

动规不解释。

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