tasks a-s

Task/Semordnilap/AWK/semordnilap.awk

@@ -0,0 +1,20 @@
+# syntax: GAWK -f SEMORDNILAP.AWK unixdict.txt
+{ arr[$0]++ }
+END {
+    PROCINFO["sorted_in"] = "@ind_str_asc"
+    for (word in arr) {
+      rword = ""
+      for (j=length(word); j>0; j--) {
+        rword = rword substr(word,j,1)
+      }
+      if (word == rword) { continue } # palindrome
+      if (rword in arr) {
+        if (word in shown || rword in shown) { continue }
+        shown[word]++
+        shown[rword]++
+        if (n++ < 5) { printf("%s %s\n",word,rword) }
+      }
+    }
+    printf("%d words\n",n)
+    exit(0)
+}