Added fannkuch example.

resources/examples/fannkuch-redux.c3

@@ -0,0 +1,81 @@
+module fannkuch;
+import std::mem;
+
+macro int max(int a, int b)
+{
+    return a > b ? a : b;
+}
+
+func int fannkuchredux(int n)
+{
+    int* perm = mem::alloc($sizeof(int), n);
+    int* perm1 = mem::alloc($sizeof(int), n);
+    int* count = mem::alloc($sizeof(int), n);
+    int maxFlipsCount;
+    int permCount;
+    int checksum;
+
+    for (int i = 0; i < n; i++) perm1[i] = i;
+
+    int r = n;
+
+    while (1)
+    {
+        for (; r != 1; r--) count[r - 1] = r;
+
+        for (int i = 0; i < n; i++) perm[i] = perm1[i];
+
+        int flipsCount = 0;
+        int k;
+
+        while (!((k = perm[0]) == 0))
+        {
+            int k2 = (k + 1) >> 1;
+            for (int i = 0; i < k2; i++)
+            {
+                int temp = perm[i];
+                perm[i] = perm[k - i];
+                perm[k - i] = temp;
+            }
+            flipsCount++;
+        }
+
+        maxFlipsCount = @max(maxFlipsCount, flipsCount);
+        checksum += permCount % 2 == 0 ? flipsCount : -flipsCount;
+
+        /* Use incremental change to generate another permutation */
+        while (1)
+        {
+            if (r == n)
+            {
+                printf("%d\n", checksum);
+                return maxFlipsCount;
+            }
+
+            int perm0 = perm1[0];
+            int i = 0;
+            while (i < r)
+            {
+                int j = i + 1;
+                perm1[i] = perm1[j];
+                i = j;
+            }
+            perm1[r] = perm0;
+            count[r] = count[r] - 1;
+            if (count[r] > 0) break;
+            r++;
+        }
+        permCount++;
+    }
+    return 0;
+}
+
+extern func int atoi(char *s);
+extern func int printf(char *s, ...);
+
+func int main(int argc, char** argv)
+{
+    int n = argc > 1 ? atoi(argv[1]) : 7;
+    printf("Pfannkuchen(%d) = %d\n", n, fannkuchredux(n));
+    return 0;
+}