) get "input.ivy"

dims = 101 103 # width, height

op t steps A = (A[;1 2] + t * A[;3 4]) mod dims

op show coords =
    pic = (*/dims) rho '.'
    pic[dims decode transp coords] = '#'
    transp dims rho pic

op qscore coords =
    x = coords[;1]
    y = coords[;2]
    m = floor dims / 2
    q1 = +/ (x < m[1]) and (y < m[2])
    q2 = +/ (x > m[1]) and (y < m[2])
    q3 = +/ (x < m[1]) and (y > m[2])
    q4 = +/ (x > m[1]) and (y > m[2])
    */(q1, q2, q3, q4)

# qscore@ (iota */dims) @steps A

op v minq t =
    t < 0: v[1]
    q = qscore (t steps v[3])
    q < v[2]: (t, q, box v[3]) minq (t-1)
    v minq (t-1)

op find A = (-1 1e100, box A) minq (*/dims)

#show 8270 steps input
qscore 100 steps input

t = find input
show (t steps input)
"t = ", t