javascript - 将数字数组缩减为固定长度的较小数字数组

Question

假设我有一个数组，它的项目长度太大对于某些maxLength

var maxLength = 3;
var arr = [1,2,3,4,5];
var tooBig = arr.length > maxLength;

是否有优化的算法通过组合项目值来减少这个数组的长度？

if(tooBig){
  var newArr = refactor(arr, maxLength);
  console.log(newArr); //[5,5,5]
}

尽可能均匀地重新分配很重要:

//Could be reduced more evenly like above
console.log(newArr); //[1,6,8]

Answer 1

基本思路是获取当前数组的总和。提取提醒，并在没有提醒的情况下得到平均值。然后新建一个数组，只要reminder大于0，就用平均值+1填充。

function refactor(arr, maxLength) {
  var sum = arr.reduce(function(s, n) {
    return s + n;
  });
  
  var remainder = sum % maxLength;
  
  var average = (sum - remainder) / maxLength;
  
  var arr = [];
  
  for(var i = 0; i < maxLength; i++) {
    arr.push(average + (i < remainder));
  }
  
  return arr;
}

var maxLength = 3;
var arr = [1,2,3,4,6];
var tooBig = arr.length > maxLength;

if(tooBig){
  var newArr = refactor(arr, maxLength);
  console.log(newArr); //[6,5,5]
}

如果不需要数组项是整数，可以直接取平均值，设置为每个数组项的值:

function refactor(arr, maxLength) {
  var average = arr.reduce(function(s, n) {
    return s + n;
  }) / maxLength;
  
  var arr = [];
  
  for(var i = 0; i < maxLength; i++) {
    arr.push(average);
  }
  
  return arr;
}

var maxLength = 3;
var arr = [1.7,2.4,3,4,6.934];
var tooBig = arr.length > maxLength;

if(tooBig){
  var newArr = refactor(arr, maxLength);
  console.log(newArr);
}