function greedy(values, weights, capacity){
  var returnValue = 0
  var remainCapacity = capacity
  var sortArray = []
  values.map((cur, index) =>{
    sortArray.push({
      'value': values[index],
      'weight': weights[index],
      'ratio': values[index]/weights[index]
    })
  })
  sortArray.sort(function(a, b){
    return b.ratio > a.ratio
  })
  console.log(sortArray)
  sortArray.map((cur,index) => {
    var num = parseInt(remainCapacity/cur.weight)
    console.log(num)
    remainCapacity -= num*cur.weight
    returnValue += num*cur.value
  })
  return returnValue
}
var items = ['A','B','C','D']
var values = [50,220,60,60]
var weights = [5,20,10,12]
var capacity = 32 //背包容积
greedy(values, weights, capacity) // 320