compare-oriented-cell/test/brute.js

Test if two sets of integers are equal up to an even permutation

'use strict'

var tape = require('tape')
var compare = require('../compare')

tape('brute force check', function(t) {
  function seq(d, n, cb) {
    var comb = new Array(d)
    function rec(i) {
      if(i === d) {
        cb(comb)
      } else for(var j=0; j<n; ++j) {
        comb[i] = j
        rec(i+1)
      }
    }
    rec(0)
  }

  function parity(s) {
    var sgn = 1
    for(var i=0; i<s.length; ++i) {
      for(var j=0; j<i; ++j) {
        if(s[i] < s[j]) {
          sgn *= -1
        } else if(s[i] === s[j]) {
          sgn = 0
        }
      }
    }
    return sgn
  }

  for(var i=1; i<=4; ++i) {
    seq(i, 5, function(a) {
      seq(i, 5, function(b) {
        var d = compare(a, b)
        var x = a.slice().sort().join()
        var y = b.slice().sort().join()
        if(x === y && parity(a) === parity(b)) {
          t.ok(d === 0, a.join() + ' == ' + b.join())
        } else {
          t.ok(d !== 0, a.join() + ' != ' + b.join())
        }
      })
    })
  }

  t.end()
})