JavaScript 中是否有一种有效的算法可以在较大的数组集中查找不同数组的数量？

Question

给定以下数组

let array = [[1, 2], [1, 2], [3, 4], [5, 6], [2, 1]]

I want to return the number of distinct arrays in this set. So the example above should return 3. How do I achieve this? I tried the code below, but it does not give the right answer

let distinct = 0
for (let i = 0; i < array.length; i++) {

  for (let j = i + 1; j < array.length - i; j++) {
    let difference = ingredients[i].filter(x => !array[j].includes(x))
     if (difference.length > 0) {
       distinct += 1;   
     } 
   }
 }

 return distinct;

Answer 1

If the order inside a sub item matters

Use Array.map() to convert each sub-array into a string (I've used String() as suggested by @trincot), create a Set from the array to remove duplicates, and get the size of the Set:

const array = [[1, 2], [1, 2], [3, 4], [5, 6]]

const distinct = new Set(array.map(String))

console.log(distinct.size)

If the order doesn't matter

Sort each sub item, and then convert to string:

const array = [[2, 1], [1, 2], [3, 4], [5, 6]]

const distinct = new Set(array.map(o => String(o.sort())))

console.log(distinct.size)