1
var replacement = (N, k) => {
2
    let result = [];
3
    if (N < 0) {
4
        console.log('N值不能为负数')
5
    } else if (k < 1) {
6
        console.log('k值不能为0和负数')
7
    } else if (k > N) {
8
        console.log('k值不能大于置换长度')
9
    } else {
10
        //将N值转化为数组
11
        let data = []
12
        for (let i = 1; i <= N; i++) {
13
            data.push(i)
14
        }
15
        //构建多叉树树干
16
        getBranch(data).map((p) => {
17
            //开始遍历
18
            dataToTree(getBranch(p.data), 0, [p.index]);
19
        })
20
    }
21
    //获取当前分支下可置换数组
22
    function getBranch(arr) {
23
        let data = []
24
        for (let i = 0; i < arr.length; i++) {
25
            let data_copy = JSON.parse(JSON.stringify(arr));
26
            let index = data_copy.splice(i, 1)
27
            data.push({
28
                index: index[0],
29
                data: data_copy
30
            })
31
        }
32
        return data;
33
    }
34
    //多叉树
35
    function dataToTree(d, t, e) {
36
        //d为数据,t为次数,e为遍历继承的数据
37
        //多叉树构建深度
38
        if (t < k - 1) {
39
            d.map((p) => {
40
                if (p.data.length >= 1) { //如果还有分支就再次遍历
41
                    let e2 = JSON.parse(JSON.stringify(e));
42
                    let t2 = t + 1;
43
                    e2.push(p.index)
44
                    dataToTree(getBranch(p.data), t2, e2)
45
                } else { //没有了就将结果放入result数组
46
                    let e2 = JSON.parse(JSON.stringify(e));
47
                    e2.push(p.index)
48
                    result.push(e2);
49
                }
50
            });
51
        } else {
52
            result.push(e);
53
        }
54
    }
55
    return result;
56
}
57
//示例
58
var replaceResult = replacement(4, 3)
59
console.log(replaceResult)