check-access-fannkuch.js

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/* The Great Computer Language Shootout

   http://shootout.alioth.debian.org/

   contributed by Isaac Gouy */

function fannkuch(n) {

   var check = 0;

   var perm = Array(n);

   var perm1 = Array(n);

   var count = Array(n);

   var maxPerm = Array(n);

   var maxFlipsCount = 0;

   var m = n - 1;

   for (var i = 0; i < n; i++) perm1[i] = i;

   var r = n;

   while (true) {

      // write-out the first 30 permutations

      if (check < 30){

         var s = "";

         for(var i=0; i<n; i++) s += (perm1[i]+1).toString();

         check++;

      while (r != 1) { count[r - 1] = r; r--; }

      if (!(perm1[0] == 0 || perm1[m] == m)) {

         for (var i = 0; i < n; i++) perm[i] = perm1[i];

         var flipsCount = 0;

         var k;

         while (!((k = perm[0]) == 0)) {

            var k2 = (k + 1) >> 1;

            for (var i = 0; i < k2; i++) {

               var temp = perm[i]; perm[i] = perm[k - i]; perm[k - i] = temp;

            flipsCount++;

         if (flipsCount > maxFlipsCount) {

            maxFlipsCount = flipsCount;

            for (var i = 0; i < n; i++) maxPerm[i] = perm1[i];

      while (true) {

         if (r == n) return maxFlipsCount;

         var perm0 = perm1[0];

         var i = 0;

         while (i < r) {

            var j = i + 1;

            perm1[i] = perm1[j];

            i = j;

         perm1[r] = perm0;

         count[r] = count[r] - 1;

         if (count[r] > 0) break;

         r++;

var n = 8;

var ret = fannkuch(n);

assertEq(ret, 22)