vector<int> getRow(int rowIndex) {
vector<int> res;
if(rowIndex<0) return res;
res.assign(rowIndex+1,0);
for(int i=0;i<=rowIndex;i++){
if(i==0)
{
res[i]=1;
continue;
}
for(int j=rowIndex;j>0;j--){
res[j]+=res[j-1];
}
}
return res;
}