Initial data commit

Task/Burrows-Wheeler-transform/Go/burrows-wheeler-transform.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+    "fmt"
+    "sort"
+    "strings"
+)
+
+const stx = "\002"
+const etx = "\003"
+
+func bwt(s string) (string, error) {
+    if strings.Index(s, stx) >= 0 || strings.Index(s, etx) >= 0 {
+        return "", fmt.Errorf("String can't contain STX or ETX")
+    }
+    s = stx + s + etx
+    le := len(s)
+    table := make([]string, le)
+    table[0] = s
+    for i := 1; i < le; i++ {
+        table[i] = s[i:] + s[:i]
+    }
+    sort.Strings(table)
+    lastBytes := make([]byte, le)
+    for i := 0; i < le; i++ {
+        lastBytes[i] = table[i][le-1]
+    }
+    return string(lastBytes), nil
+}
+
+func ibwt(r string) string {
+    le := len(r)
+    table := make([]string, le)
+    for range table {
+        for i := 0; i < le; i++ {
+            table[i] = r[i:i+1] + table[i]
+        }
+        sort.Strings(table)
+    }
+    for _, row := range table {
+        if strings.HasSuffix(row, etx) {
+            return row[1 : le-1]
+        }
+    }
+    return ""
+}
+
+func makePrintable(s string) string {
+    // substitute ^ for STX and | for ETX to print results
+    t := strings.Replace(s, stx, "^", 1)
+    return strings.Replace(t, etx, "|", 1)
+}
+
+func main() {
+    tests := []string{
+        "banana",
+        "appellee",
+        "dogwood",
+        "TO BE OR NOT TO BE OR WANT TO BE OR NOT?",
+        "SIX.MIXED.PIXIES.SIFT.SIXTY.PIXIE.DUST.BOXES",
+        "\002ABC\003",
+    }
+    for _, test := range tests {
+        fmt.Println(makePrintable(test))
+        fmt.Print(" --> ")
+        t, err := bwt(test)
+        if err != nil {
+            fmt.Println("ERROR:", err)
+        } else {
+            fmt.Println(makePrintable(t))
+        }
+        r := ibwt(t)
+        fmt.Println(" -->", r, "\n")
+    }
+}