[js] 排列组合矩阵实现

[VaJoy]

有这么几个变量：

• a 其值可能为 0、1
• b 其值可能为 3、4、5
• c 其值可能为 6、7

实现一个函数 getArranging 可以返回它们的可能值的排列组合二维数组：

function getArranging( ){
      //TODO - 返回参数的排列组合
}

var a = [0, 1];
var b = [3, 4, 5];
var c = [6, 7];

var ret = getArranging( a, b, c );
// ret 值为：
/**
[ [0,3,6], [0,3,7], [0,4,6], [0,4,7], [0,5,6], [0,5,7], [1,3,6], [1,3,7], [1,4,6], [1,4,7], [1,5,6], [1,5,7] ]
**/

[blade254353074]

function cartesian (...lists) {
  return lists
    .map(list => list.map(item => [item]))
    .reduce((listsA, listsB) =>
      listsA.reduce((list, listA) =>
        list.concat(
          listsB.map(listB => listA.concat(listB))
        ), []
      )
    )
}

[Jiasm]

(() => {
  function getArranging (...list) {
    return build(list)
  }

  function build (list, result = list.shift()) {
    return !list.length ? result : build(list, [].concat(...list.shift().map(item =>
      result.map(resultItem => 
        [].concat(item, resultItem)
      )
    )))
  }

  let a = [0, 1]
  let b = [3, 4, 5]
  let c = [6, 7]

  let ret = getArranging( a, b, c )

  console.log(JSON.stringify(ret))
})()

[uinz]

function getArranging(...args: number[][]) {
    const result = [];

    (function loop(tmp: number[] = []) {
        if (tmp.length === args.length) {
            result.push(tmp)
            return
        }
        const values = args[tmp.length]
        values.forEach(value => {
            loop([...tmp, value])
        })
    })();

    return result;

}

console.log(
    getArranging([0, 1], [3, 4, 5], [6, 7])
);

[lshnltt]

function getArranging(...list){
//TODO - 返回参数的排列组合
return list.reduce((result, curr, listIndex) => {
curr.forEach((item, index) => {
let insertCount = len(list)/curr.length;
let interval = len(list.slice(listIndex));
let sufixLen = len(list.slice(listIndex + 1));
let startPosition = index * sufixLen;
Array.from(new Array(insertCount)).forEach((_item, _index) => {
let round = (Math.ceil((_index + 1) / sufixLen) - 1) * interval;
position = startPosition + ((_index % sufixLen == 0 || !sufixLen) ? round : round + _index % sufixLen);
result[position] = result[position] || [];
result[position][listIndex] = item;
});
});
return result;
}, []);
}
function len(list) {
return list.reduce((result, curr) => {
result *= curr.length;
return result;
}, 1);
}
var a = [0, 1];
var b = [3, 4, 5];
var c = [6, 7];
var d = [8, 9, 10]
var ret = getArranging( a, b, c, d );
console.log(ret);