为什么我对 powerset 问题的解决方案不正确？我已经包括了我的递归和迭代方法[重复]

Question

问题基本上是在给定一个唯一整数数组的情况下生成所有子集。

例如powerSet[1,2,3] 应该返回[[], [1], [2], [3], [1,2], [1,3], [2,3], [1,2,3]]

这是我的递归尝试：

function powerset(array) {
  // Write your code here.
    let set = [[]];
    powersetHelper(array, [], set);
    return set;
}

function powersetHelper(array, subset, set) {
    if (array.length === 0) return;
    for (let i = 0; i < array.length; i++) {
        subset.push(array[i]);
        set.push(subset);
    }
    let newArr = array.slice(1);
    powersetHelper(newArr, [], set)
}

为什么这会返回 [[], [1, 2, 3], [1, 2, 3], [1, 2, 3], [2, 3], [2, 3], [3]] 而不是正确的解决方案？

此外，我反复尝试如下：

function powerset(array) {
  // Write your code here.
    let subset = [];
    let set = [[]];
    while (array.length > 0) {
        for (let j = 0; j < array.length; j++) {
            let num = array[j];
            subset.push(num);
            set.push(subset);
        }
        array = array.slice(1);
    }
    return set;
}

这也是不正确的，并且以某种方式返回了我在下面的内容，即使它似乎与我的递归解决方案的逻辑相同

[
  [],
  [1, 2, 3, 2, 3, 3],
  [1, 2, 3, 2, 3, 3],
  [1, 2, 3, 2, 3, 3],
  [1, 2, 3, 2, 3, 3],
  [1, 2, 3, 2, 3, 3],
  [1, 2, 3, 2, 3, 3]
]

Answer 1

您需要在没有对象引用的情况下进行复制。

function powerSet(array) {
    // Write your code here.
    let set = [[]];
    powersetHelper(array, [], set);
    return set;
}

function powersetHelper(array, subset, set) {
    if (array.length === 0) return;
    for (let i = 0; i < array.length; i++) {
        subset.push(array[i]);
        set.push([...subset]); // take copy without object reference
    }
    let newArr = array.slice(1);
    powersetHelper(newArr, [], set)
}

console.log(powerSet([1, 2, 3])); // [[], [1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]

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第二个，同样的问题

function powerSet(array) {
    // Write your code here.
    let subset = [];
    let set = [[]];
    while (array.length > 0) {
        for (let j = 0; j < array.length; j++) {
            let num = array[j];
            subset.push(num);
            set.push([...subset]);
        }
        array = array.slice(1);
    }
    return set;
}

console.log(powerSet([1, 2, 3])); // [[], [1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]

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