Data commit

Task/Esthetic-numbers/Go/esthetic-numbers.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+    "fmt"
+    "strconv"
+)
+
+func uabs(a, b uint64) uint64 {
+    if a > b {
+        return a - b
+    }
+    return b - a
+}
+
+func isEsthetic(n, b uint64) bool {
+    if n == 0 {
+        return false
+    }
+    i := n % b
+    n /= b
+    for n > 0 {
+        j := n % b
+        if uabs(i, j) != 1 {
+            return false
+        }
+        n /= b
+        i = j
+    }
+    return true
+}
+
+var esths []uint64
+
+func dfs(n, m, i uint64) {
+    if i >= n && i <= m {
+        esths = append(esths, i)
+    }
+    if i == 0 || i > m {
+        return
+    }
+    d := i % 10
+    i1 := i*10 + d - 1
+    i2 := i1 + 2
+    if d == 0 {
+        dfs(n, m, i2)
+    } else if d == 9 {
+        dfs(n, m, i1)
+    } else {
+        dfs(n, m, i1)
+        dfs(n, m, i2)
+    }
+}
+
+func listEsths(n, n2, m, m2 uint64, perLine int, all bool) {
+    esths = esths[:0]
+    for i := uint64(0); i < 10; i++ {
+        dfs(n2, m2, i)
+    }
+    le := len(esths)
+    fmt.Printf("Base 10: %s esthetic numbers between %s and %s:\n",
+        commatize(uint64(le)), commatize(n), commatize(m))
+    if all {
+        for c, esth := range esths {
+            fmt.Printf("%d ", esth)
+            if (c+1)%perLine == 0 {
+                fmt.Println()
+            }
+        }
+    } else {
+        for i := 0; i < perLine; i++ {
+            fmt.Printf("%d ", esths[i])
+        }
+        fmt.Println("\n............\n")
+        for i := le - perLine; i < le; i++ {
+            fmt.Printf("%d ", esths[i])
+        }
+    }
+    fmt.Println("\n")
+}
+
+func commatize(n uint64) string {
+    s := fmt.Sprintf("%d", n)
+    le := len(s)
+    for i := le - 3; i >= 1; i -= 3 {
+        s = s[0:i] + "," + s[i:]
+    }
+    return s
+}
+
+func main() {
+    for b := uint64(2); b <= 16; b++ {
+        fmt.Printf("Base %d: %dth to %dth esthetic numbers:\n", b, 4*b, 6*b)
+        for n, c := uint64(1), uint64(0); c < 6*b; n++ {
+            if isEsthetic(n, b) {
+                c++
+                if c >= 4*b {
+                    fmt.Printf("%s ", strconv.FormatUint(n, int(b)))
+                }
+            }
+        }
+        fmt.Println("\n")
+    }
+
+    // the following all use the obvious range limitations for the numbers in question
+    listEsths(1000, 1010, 9999, 9898, 16, true)
+    listEsths(1e8, 101_010_101, 13*1e7, 123_456_789, 9, true)
+    listEsths(1e11, 101_010_101_010, 13*1e10, 123_456_789_898, 7, false)
+    listEsths(1e14, 101_010_101_010_101, 13*1e13, 123_456_789_898_989, 5, false)
+    listEsths(1e17, 101_010_101_010_101_010, 13*1e16, 123_456_789_898_989_898, 4, false)
+}