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Javascript – find all subset of arrays in js

Here I have written a program that will find all the subsets array, like if the array is [1, 2, 3], and I want output like [[], 2],, 2, , [2, 1], 3, , [3, 1], [3, 2], [3

I have written a program that represents the binary logic representation. The output is not coming as expected.

Can you please rectify and modify that programme?

const getAllSubsets = arr => {
    let n = arr.length
    let add = []
    for (let i = 0; i < (1 << n); i++) {
        for (let j = 0; j < n; j++) {
            if ((1 << j) & i) {
                add.push([arr[j]])
            }
        }
    }

    return add
}
      
console.log(getAllSubsets([1,2,3]))
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2

Answers


  1. 0

    You could take a recursive approach and get arrays with undefined plus rest and the value plus rest.

    const
    getAllSubsets = ([value, ...rest]) => {
       const sub = rest.length ? getAllSubsets(rest) : [[]];
       return [
           ...sub.flatMap(a => [[undefined, ...a]]),
           ...sub.flatMap(a => [[array[0], ...a]]),
       ];
    };

console.log(getAllSubsets([1, 2, 3]));
    .as-console-wrapper { max-height: 100% !important; top: 0; }
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  2. 0

    You need two storage arrays: one for all subsets, and one for the current one. The overall schema of your code would be like this:

    const getAllSubsets = arr => {
    let subsets = []
    
    OUTER LOOP {
        let subset = []
        INNER LOOP {
            if ...
                subset.push(arr[j])
        }
        subsets.push(subset)
    }

    return subsets
}

    Good luck!

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