class Solution {

public:

vector<vector<int>> generate(int numRows) {

vector<vector<int>> triangle;

if(numRows <1)

return triangle;

vector<int> temp(1,1);

triangle.push_back(temp);

for(int i =2 ;i<=numRows;i++)

{

temp.push_back(0); //加一个值进来

vector<int> cur = temp;

for(int j = 1;j<i;j++)

cur[j] = temp[j] + temp[j-1]; //得到每一层的vector

temp = cur;

triangle.push_back(temp);

}

return triangle;

}

};