day 14 ivy solution

day14/sol.ivy

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+
+) 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