全排列

普通对象全排列

function permute(arr) {
  function generatePermutations(currentArr, remainingArr) {
    if (remainingArr.length === 0) {
      permutations.push(currentArr);
    } else {
      for (let i = 0; i < remainingArr.length; i++) {
        const newArr = currentArr.slice();
        newArr.push(remainingArr[i]);
        const restArr = remainingArr.slice(0, i).concat(remainingArr.slice(i + 1));
        generatePermutations(newArr, restArr);
      }
    }
  }

  const permutations = [];
  generatePermutations([], arr);
  return permutations;
}

// 示例用法
const inputArray = ['A', 'B', 1, 2];
const result = permute(inputArray);
console.log(result);

不定长二维数组的全排列

// 输入 [['A', 'B', ...], [1, 2], ['a', 'b'], ...]
// 输出 ['A1a', 'A1b', ....]

let arrays = [
  ['A', 'B', 'C'],
  [1, 2],
  ['a', 'b']
];

function getArrayByArrays(inputArray) {
  let result = [''];
  for (let i = 0; i < inputArray.length; i++) {
    result = getValuesByArray(result, inputArray[i]);
  }
  return result;
}
function getValuesByArray(res, remainingArray) {
  let midArray = [];
  for (let i = 0; i < res.length; i++) {
    for (let j = 0; j < remainingArray.length; j++) {
      midArray.push(res[i] + remainingArray[j]);
    }
  }
  return midArray;
}
let result = getArrayByArrays(arrays);
console.log('result', result);