Data commit

Task/Self-describing-numbers/Go/self-describing-numbers-1.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "strings"
+)
+
+// task 1 requirement
+func sdn(n int64) bool {
+    if n >= 1e10 {
+        return false
+    }
+    s := strconv.FormatInt(n, 10)
+    for d, p := range s {
+        if int(p)-'0' != strings.Count(s, strconv.Itoa(d)) {
+            return false
+        }
+    }
+    return true
+}
+
+// task 2 code (takes a while to run)
+func main() {
+    for n := int64(0); n < 1e10; n++ {
+        if sdn(n) {
+            fmt.Println(n)
+        }
+    }
+}

Task/Self-describing-numbers/Go/self-describing-numbers-2.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "strings"
+    "time"
+)
+
+func selfDesc(n uint64) bool {
+    if n >= 1e10 {
+        return false
+    }
+    s := strconv.FormatUint(n, 10)
+    for d, p := range s {
+        if int(p)-'0' != strings.Count(s, strconv.Itoa(d)) {
+            return false
+        }
+    }
+    return true
+}
+
+func main() {
+    start := time.Now()
+    fmt.Println("The self-describing numbers are:")
+    i := uint64(10)   // self-describing number must end in 0
+    pw := uint64(10)  // power of 10
+    fd := uint64(1)   // first digit
+    sd := uint64(1)   // second digit
+    dg := uint64(2)   // number of digits
+    mx := uint64(11)  // maximum for current batch
+    lim := uint64(9_100_000_001) // sum of digits can't be more than 10
+    for i < lim {
+        if selfDesc(i) {
+            secs := time.Since(start).Seconds()
+            fmt.Printf("%d (in %.1f secs)\n", i, secs)
+        }
+        i += 10
+        if i > mx {
+            fd++
+            sd--
+            if sd >= 0 {
+                i = fd * pw
+            } else {
+                pw *= 10
+                dg++
+                i = pw
+                fd = 1
+                sd = dg - 1
+            }
+            mx = i + sd*pw/10
+        }
+    }
+    osecs := time.Since(start).Seconds()
+    fmt.Printf("\nTook %.1f secs overall\n", osecs)
+}