js/src/correct/check-access-fannkuch.js

   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 print(ret == 22)