Question

我想生成一个包含6个元素的数组，总和始终为N。只有正整数。

var arr = generateArray();
arr.length === 6; //always true
arr.reduce((a,b) => a + b) === 16; //also always true

基本上是一种更优雅的执行方式：

rndInt = (max) => Math.floor(Math.random() * Math.floor(max)),
rndAssign = (piles, items) => {
    let groups = new Int8Array(piles);
    for (i = 0; i < items; i++) {
        groups[rndInt(piles)]++
    }
    return groups
},

Answer 1

您可以尝试以下操作：

const generateArray = (sum = 16, groupsQty = 6) => {
  this.currentSum = 0;
  // create empty array of given length and populate it with items in sum not exceeding given sum
  return Array.from({length: groupsQty}).reduce((res, curr, ind) => {
    const item = ind === groupsQty - 1 ? sum - this.currentSum : Math.floor(Math.random() * (sum + 1 - this.currentSum));
    // store current sum
    this.currentSum += item;
    return [
      ...res, 
      item
    ]
  }, [])
};

const arr = generateArray();
console.log(arr);
console.log('LENGTH:', arr.length);
console.log('SUM:', arr.reduce((a, b) => a + b, 0));

Answer 2

您可以使用带有值的数组

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]或
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]，

取决于您是否也想要零，并使用brte force方法通过取六个元素来获得总和为16的值的任何可能组合。

为进一步选择，您可以选择一个随机数组。此随机值呈正态分布。

结果可能需要更长的时间才能运行。

function get6(values) {

    function iter(temp) {
        return function (v) {
            var t = temp.concat(v);
            if (t.length === 6) {
                if (t.reduce(add) === 16) {
                    result.push(t);
                }
                return;
            }
            values.forEach(iter(t));
        };
    }
    
    const
        add = (a, b) => a + b,
        result = [];

    values.forEach(iter([]));
    return result;
}

var small = get6([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]),
    big = get6([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]);

console.log(small.length);                //  3003
console.log(small.map(a => a.join(' ')));
console.log(big.length);                  // 20349
console.log(big.map(a => a.join(' ')));

.as-console-wrapper { max-height: 100% !important; top: 0; }

如何将N个项目分为6个随机组，使总和始终相同？

2 个答案: