サブ　permutation.js　　　Last modified: Mar 25, 2004
var array0, nr, nc, um, t, ntrue, denom, stat_val, nc1, nr1, array1, array2
var EPSILON = 1e-14
var MAXLOOP = 2000
var CRITERION = 5000

function com(n, m)
{
  var k, i
  var retv = 1
  k = Math.min(n-m, m)
  for (i = 1; i <= k; i++) {
    retv *= (n -i+1)/i
  }
  return retv
}

function decomp(data, a)
{
  var i, j, n = 0
  for (i = 0; i < data.length; i++) {
    for (j = 0; j < data[i].length; j++) {
      a[n++] = data[i][j]
    }
  }
  return n
}

function found()
{
  var i, n1, n2
  n1 = n2 = 0
  for (i = 0; i < nc; i++) {
    if (um[0][i]) {
      array1[n1++] = array0[i]
    }
    else {
      array2[n2++] = array0[i]
    }
  }
  if (stat(array1, n1, array2, n2) >= stat_val-EPSILON) {
    ntrue++
  }
}

function search(x, y)
{
  var t
  if (y == 0) {
    found()
  }
  else if (x == 0) {
    if ((t = um[0][0]-um[y][0]) < 0) {
      return
    }
    um[0][0] = t
    search(nc1, y-1)
    um[0][0] += um[y][0]
  }
  else {
    search(x-1, y)
    while (um[y][0] && um[0][x]) {
      ++um[y][x]
      --um[y][0]
      --um[0][x]
      search(x-1, y)
    }
    um[y][0] += um[y][x]
    um[0][x] +=um[y][x]
    um[y][x] = 0
  }
}

function exact(n1, n2)
{
  var i

  ntrue = 0
  denom = com(n1+n2, n1)
  um = new Array(nr)
  for (i = 0; i < nr; i++) {
    um[i] = new Array(nc)
  }

  for (i = 0; i < nc; i++) {
    um[0][i] = 1
    um[1][i] = 0
  }
  um[1][0] = n2
  nc1 = nc-1
  nr1 = nr-1

  search(nc1, nr1)
}

function approx(n1, n2)
{
  var i, j, k, n, temp, a
  ntrue = 0
  denom = MAXLOOP
  n = n1+n2
  a = new Array(n)
  for (i = 0; i < n; i++) {
    a[i] = i
  }
  for (i = 0; i < MAXLOOP; i++) {
    for (j = 0; j < n; j++) {
      for (;;) {
        k = Math.floor(Math.random()*n)
        if (k >= 0 && k < n) break
      }
      temp = a[k]
      a[k] = a[j]
      a[j] = temp
    }
    for (j = 0; j < n1; j++) {
      array1[j] = array0[a[j]]
    }
    for (j = 0; j < n2; j++) {
      array2[j] = array0[a[j+n1]]
    }
    if (stat(array1, n1, array2, n2) >= stat_val-EPSILON) {
      ntrue++
    }
  }
}