如何找到一个数字，该数字是在数组（Javascript）中添加哪些元素的结果？

Question

For example, there is an array arr[1,2,4,8,16,32,64,128] , each element represents a permission. This is the number used for permission assignment.

One number which is definitely the sum of an element or several elements in an array.

For example:

1 = arr[0]

6 = arr[1]+arr[2]

11 = arr[0]+arr[1]+arr[3]

17 = 1 + 16

171 = 1 +2 +8 +32 +128

How to find this element or several elements coding with js?

Thanks for your help.

Answer 1

Even though you probably don't really care what's going on here since it very much smells like an assignment of some sort, this is exactly how answerer feels when asker do not provide enough information that helps with answering the question.

 const arr = [1, 2, 4, 8, 16, 32, 64, 128] const getElementIndexes = (n) => { return arr.slice().reverse().reduce((accumulator, currentValue) => { if (n >= currentValue) { accumulator.unshift(arr.indexOf(currentValue)) n = n - currentValue } return accumulator }, []) } console.log(getElementIndexes(1)) console.log(getElementIndexes(6)) console.log(getElementIndexes(11)) console.log(getElementIndexes(17)) console.log(getElementIndexes(171))