Anti Diagonals

 https://www.interviewbit.com/problems/anti-diagonals/

vector<vector<int> > Solution::diagonal(vector<vector<int> > &A) {

    int x=A.size();

    vector<vector<int> >res(2*x-1);

    int count=0;

    //upper triangle

    for(int i=0;i<x;i++){

        int row=0,col=i;

        while(row<x && col>=0){

            res[count].push_back(A[row][col]);

            row++;

            col--;

        }

        count++;

    }

    //lower triangle

    for(int i=1;i<x;i++){

        int row=i,col=x-1;

        while(row<x && col>=0){

            res[count].push_back(A[row][col]);

            row++;

            col--;

        }

        count++;

    }

    return res;

}