Last letter-first letter: Difference between revisions

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@@ Line 91: / Line 91: @@
   rufflet trapinch haxorus seaking girafarig gabite exeggcute
   emolga audino</pre>
-Runtime: about 1.23 seconds.
+Runtime: about 1.23 seconds, dmd compiler.
 This is the same program, with some low-level optimizations:
@@ Line 97: / Line 97: @@
        std.typecons, std.exception;
+struct Ref {
-Tuple!(string[], int) findLongestChain(in string[] items) {
-    static struct Ref {
+    ushort index;
-        ushort index;
+    char lastChar, firstChar;
+}
-        char lastChar, firstChar;
+__gshared int nSolutions;
+__gshared Ref[] refs, longestPathRefs;
+/// tally statistics
+void search(in size_t currLen) {
+    if (currLen == longestPathRefs.length) {
+        nSolutions++;
+    } else if (currLen > longestPathRefs.length) {
+        nSolutions = 1;
+        longestPathRefs = refs[0 .. currLen].dup;
     }
+    // recursive search
+    const dchar lastChar = refs[currLen - 1].lastChar;
+    foreach (i; currLen .. refs.length)
+        if (refs[i].firstChar == lastChar) {
+            const aux = refs[currLen];
+            refs[currLen] = refs[i];
+            refs[i] = aux;
+            search(currLen + 1);
+            refs[i] = refs[currLen];
+            refs[currLen] = aux;
+        }
+}
+Tuple!(string[], int) findLongestChain(in string[] items) {
     foreach (item; items)
         enforce(item.length > 1);
-    int nSolutions;
-    Ref[] refs, longestPathRefs;
     foreach (ushort i, item; items)
         refs ~= Ref(i, item[0], item[$-1]);
-    /// tally statistics
-    void search(in size_t currLen) {
-        if (currLen == longestPathRefs.length) {
-            nSolutions++;
-        } else if (currLen > longestPathRefs.length) {
-            nSolutions = 1;
-            longestPathRefs = refs[0 .. currLen].dup;
-        }
-        // recursive search
-        const dchar lastChar = refs[currLen - 1].lastChar;
-        foreach (i; currLen .. refs.length)
-            if (refs[i].firstChar == lastChar) {
-                const aux = refs[currLen];
-                refs[currLen] = refs[i];
-                refs[i] = aux;
-                search(currLen + 1);
-                refs[i] = refs[currLen];
-                refs[currLen] = aux;
-            }
-    }
     // try each item as possible start
@@ Line 171: / Line 172: @@
         writeln("  ", sol_nsol[0][i .. min(i+7, $)].join(" "));
 }</lang>
-Runtime: about 0.79 seconds.
+Runtime: about 0.67 seconds, dmd compiler.
 =={{header|Go}}==