pascal’s triangle ii

vector<int> getRow(int rowIndex) {
    if(rowIndex == 0) return vector<int>(1,1);
    
    vector<int>res(rowIndex+1,0);
    
    //approach 1: O(N^2)
    for(int i=1; i<= rowIndex; i++){
        for(int j=i; j>=0; j--){
            if(j == i || j == 0){
                res[j] = 1;
            }
            else{
                res[j] += res[j-1];
            }
        }
    }
    /*
    //approach 2: O(N)
    for(int i=1; i<= rowIndex/2; i++){
		res[i] = res[rowIndex-i] = (long long int)res[i-1]*(rowIndex-i+1)/i;
	}
	*/
    return res;
}