js实现全排列功能

全排列功能

分解成多个子问题就行

// 递归

const fullPermutate = (str) => {
  const result = [];
  if (str.length > 1) {
    for (let i = 0; i < str.length; i += 1) {
      const cur = str[i];

      // 获取下一部分的字符串
      const restArr = str.slice(0, i) + str.slice(i + 1, str.length);

      // 将两者组合起来
      const subResult = fullPermutate(restArr);

      for (let j = 0; j < subResult.length; j += 1) {
        result.push(cur + subResult[j]);
      }
    }
  } else {
    result.push(str);
  }

  return result;
};

fullPermutate('abc');

// 回溯

const full = (str1) => {
  const result = [];

  const hs = (str, path) => {
    if (str.length === 0) {
      result.push(path.join(''));
    } else {
      for (let i = 0; i < str.length; i += 1) {
        path.push(str[i]);
        const tempStr = str.slice(0, i) + str.slice(i + 1);
        hs(tempStr, path);
        // 还原path
        path.pop();
      }
    }
  };

  hs(str1, []);
  console.log(result);
};

full('abcde');