反转长字符串中某些字符的算法

Question

我目前正在做一道编程题：

Given a string s and an integer k, reverse the first k characters for every 2k characters counting from the start of the string.

If there are fewer than k characters left, reverse all of them. If there are less than 2k but greater than or equal to k characters, then reverse the first k characters and leave the other as original.

我创建了一个程序来解决 60 个测试用例中的前 45 个，但显然在处理非常长的字符串时会崩溃。当输入 999 个字符的字符串时，最后几个字符是无意义的。

我在我的代码中看不出任何可能导致这种情况的错误。任何反馈？简单的解决方案还是构建代码的更好方法？

function reverseArrayOfChars(sArray) {
  const length = sArray.length;
  let temp;
  for (let s = 0; s < length / 2; s++) {
    temp = sArray[s];
    sArray[s] = sArray[length - 1 - s];
    sArray[length - 1 - s] = temp;
  }
  return sArray;
}

function reverseStr(s, k) {
  let sArray = s.split("");
  let newArray = []; //Final array to be returned
  let tempArray = []; //tempArray is used to store returns from reverseArrayOfChars function. These returns are then concatenated onto newArray.
  let switchBoard = 1; //Used to 'switch' between two conditions. Changes automatically every iteration of the loop.
  for (let counter = 0; counter < sArray.length; counter += k) {
    switchBoard = switchBoard === 0 ? 1 : 0;
    if (sArray.length - counter < k) {
      tempArray = reverseArrayOfChars(sArray.slice(counter));
      newArray = newArray.concat(tempArray);
      break;
    } else if (sArray.length - counter > k && sArray.length < k * 2) {
      tempArray = reverseArrayOfChars(sArray.slice(counter, counter + k));
      newArray = newArray.concat(tempArray);
      tempArray = sArray.slice(counter + k);
      newArray = newArray.concat(tempArray);
      break;
    } else if (switchBoard === 0) {
      tempArray = reverseArrayOfChars(sArray.slice(counter, counter + k));
      newArray = newArray.concat(tempArray);
    } else if (switchBoard === 1) {
      tempArray = sArray.slice(counter, counter + k);
      newArray = newArray.concat(tempArray);
    }
  }
  return newArray.join("");

Answer 1

或者，您可以试试这个示例代码：

var reverseStr = function(s, k) {
    if (k > s.length) 
        return s.split('').reverse().join('');
    
    const split = s.split('');
    
    // reverse the seg. then join it back
    for (let i = 0; i < s.length; i += 2*k) {
        const reverse = split.splice(i, k).reverse();
        split.splice(i, 0, ...reverse);
    }
    
    return split.join('');
};

反转长字符串中某些字符的算法

Algorithm for reversing certain characters in long strings

javascript

arrays

algorithm

reverse