1 /* The Great Computer Language Shootout

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

     3    contributed by Isaac Gouy */

     4 

     5 function fannkuch(n) {

     6    var check = 0;

     7    var perm = Array(n);

     8    var perm1 = Array(n);

     9    var count = Array(n);

    10    var maxPerm = Array(n);

    11    var maxFlipsCount = 0;

    12    var m = n - 1;

    13 

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

    15    var r = n;

    16 

    17    while (true) {

    18       // write-out the first 30 permutations

    19       if (check < 30){

    20          var s = "";

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

    22          check++;

    23       }

    24 

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

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

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

    28 

    29          var flipsCount = 0;

    30          var k;

    31 

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

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

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

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

    36             }

    37             flipsCount++;

    38          }

    39 

    40          if (flipsCount > maxFlipsCount) {

    41             maxFlipsCount = flipsCount;

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

    43          }

    44       }

    45 

    46       while (true) {

    47          if (r == n) return maxFlipsCount;

    48          var perm0 = perm1[0];

    49          var i = 0;

    50          while (i < r) {

    51             var j = i + 1;

    52             perm1[i] = perm1[j];

    53             i = j;

    54          }

    55          perm1[r] = perm0;

    56 

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

    58          if (count[r] > 0) break;

    59          r++;

    60       }

    61    }

    62 }

    63 

    64 var n = 8;

    65 var ret = fannkuch(n);

    66