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++;↩

      }↩

   }↩

}↩

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var n = 8;↩

var ret = fannkuch(n);↩

↩