803A - Maximal Binary Matrix - CodeForces Solution

n,k=map(int,input().split())
if k>n**2:
    print(-1)
else:
    m=n
    while (k-2*n+1)>=0 and k>0 and n>0:
        k-=2*n-1
        n-=1
    matrix=[[0 for _ in range(n)] for _ in range(n)]
    if k%2==1:
        x=k//2+1
        for _ in range(x):
            matrix[0][_],matrix[_][0]=1,1
    else:
        x=k//2
        if n>1 and k>0:
            matrix[1][1]=1
        for _ in range(x):
            matrix[0][_],matrix[_][0]=1,1
    Matrix=[[1]*m]*(m-n)+[[1]*(m-n)+matrix[_] for _ in range(n)]
    for i in range(m):
        for j in Matrix[i]:
            print(j,end=' ')
        print('')