Data commit

Task/Fraction-reduction/Wren/fraction-reduction.wren

@@ -0,0 +1,87 @@
+import "/dynamic" for Struct
+import "/fmt" for Fmt
+
+var Result = Struct.create("Result", ["n", "nine"])
+
+var toNumber = Fn.new { |digits, removeDigit|
+    var digits2 = digits.toList
+    if (removeDigit != 0) {
+        var d = digits2.indexOf(removeDigit)
+        digits2.removeAt(d)
+    }
+    var res = digits2[0]
+    var i = 1
+    while (i < digits2.count) {
+        res = res * 10 + digits2[i]
+        i = i + 1
+    }
+    return res
+}
+
+var nDigits = Fn.new { |n|
+    var res = []
+    var digits = List.filled(n, 0)
+    var used = List.filled(9, false)
+    for (i in 0...n) {
+        digits[i] = i + 1
+        used[i] = true
+    }
+    while (true) {
+        var nine = List.filled(9, 0)
+        for (i in 0...used.count) {
+            if (used[i]) nine[i] = toNumber.call(digits, i+1)
+        }
+        res.add(Result.new(toNumber.call(digits, 0), nine))
+        var found = false
+        for (i in n-1..0) {
+            var d = digits[i]
+            if (!used[d-1]) {
+                Fiber.abort("something went wrong with 'used' array")
+            }
+            used[d-1] = false
+            var j = d
+            while (j < 9) {
+                if (!used[j]) {
+                    used[j] = true
+                    digits[i] = j + 1
+                    for (k in i + 1...n) {
+                        digits[k] = used.indexOf(false) + 1
+                        used[digits[k]-1] = true
+                    }
+                    found = true
+                    break
+                }
+                j = j + 1
+            }
+            if (found) break
+        }
+        if (!found) break
+    }
+    return res
+}
+
+for (n in 2..5) {
+    var rs = nDigits.call(n)
+    var count = 0
+    var omitted = List.filled(9, 0)
+    for (i in 0...rs.count-1) {
+        var xn = rs[i].n
+        var rn = rs[i].nine
+        for (j in i + 1...rs.count) {
+            var xd = rs[j].n
+            var rd = rs[j].nine
+            for (k in 0..8) {
+                var yn = rn[k]
+                var yd = rd[k]
+                if (yn != 0 && yd != 0 && xn/xd == yn/yd) {
+                    count = count + 1
+                    omitted[k] = omitted[k] + 1
+                    if (count <= 12) {
+                        Fmt.print("$d/$d => $d/$d (removed $d)", xn, xd, yn, yd, k+1)
+                    }
+                }
+            }
+        }
+    }
+    Fmt.print("$d-digit fractions found:$d, omitted $s\n", n, count, omitted)
+}