class Solution { public: vector<int> getRow(int rowIndex) { vector<int> v; if( rowIndex < 0) return v; v.push_back(1); if(rowIndex == 0) return v; v.push_back(1); if(rowIndex == 1) return v; vector<int> v1; for(int row=2;row<=rowIndex;row++){ v1.push_back(1); int pre_len = v.size(); for(int i=0;i<pre_len-1;i++){ v1.push_back(v[i]+v[i+1]); } v1.push_back(1); v=v1; //vector 拷贝好方便啊 v1.clear(); } return v; } };