通过JS的n个列表的交集 [英] intersection of n lists via JS

问题描述

我正在研究一种算法并试图找出如何解决它，并给出以下信息：

I am working on an algorithm and trying to figure out how to solve it given the following information:

1. 我想找到n个列表之间的交集


2. 假设我有一个（正常工作）交叉点（a，b）函数


3. 假设交点（ ）只需要两个列表作为输入

所以问题看起来像这样：

So the problem would look something like this:

var a = {1, 2, 'b'}; 
var b = {2, 'b', 'b'};
var c = {2, 'b', 'c'};
var d = {'a', 'b', 'c'};

//this is the part that does not work, of course:
function intersect_all(d)
{
    //what goes in here???        
}

注意：我不想为此使用python，因为python有lang中内置的方法，我的应用程序无法使用（或js，就此而言）。我想用上面的信息解决它。

Note: I don't want to use python for this, since python has methods built into the lang that are not available for my app (or js, for that matter). I would like to solve it using the above information.

结果应该类似于

{2, 'b'}

jml

推荐答案

假设您有一系列列表：

var lists = [];
lists[0] = [1, 2, 'b']; 
lists[1] = [2, 'b', 'b'];
lists[2] = [2, 'b', 'c'];
lists[3] = ['a', 'b', 'c'];

然后你可以使用这个：

// say you call this passing the array of lists as the argument: intersect_all(lists)
function intersect_all(lists)
{
    if (lists.length == 0) return [];
    else if (lists.length == 1) return lists[0];

    var partialInt = lists[0];
    for (var i = 1; i < lists.length; i++)
    {
        partialInt = intersection(partialInt, lists[i]);
    }
    return partialInt;
}

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