javascript 解决回文索引问题

[sunhengzhe]

给定一个单词 word 和一个字符串 S，找到 S 中的所有 word 及其回文（逆序）的起始索引

function findAnswer(word, s) {
	// TODO
}

findAnswer('abc', 'abcxabcbacc'); // [0, 4, 6]

[liliuzhu]

比较笨的方法，也可以实现

findAnswer(word, str) {
    if (typeof str !== 'string' || typeof word !== 'string') {
        throw new Error('参数类型错误');
    }
    let reverse = word.split('').reverse().join('');
    let reg = new RegExp(word + '|' + reverse, 'g');
    let result = null;
    let indexArr = [];
    while ((result = reg.exec(str)) != null) {
        indexArr.push(result.index);
        reg.lastIndex = result.index + 1;
    }
    console.log(indexArr);
}

[andysongs]

const check = (str1, str2) => {
  return (str1 === str2) || (str1 === str2.split('').reverse().join(''))
}

const findAnswer = (word, s) => {
  // TODO
  if (word.length > s.length) return
  let length = word.length
  let i = 0;
  let res = [];
  while (s[i + length - 1]) {
    let sample = s.slice(i, i + length)
    console.log(sample)
    if (check(word, sample)) res.push(i)
    i++;
  }
  return res
}

console.log(findAnswer('abc', 'abcxabcbacc'));

[wycnewu]

if (check(word, sample)){ res.push(i); i = i + length} else{ i++ }

[jiangyanyun]

function findAnswer(word, s) {
let indexs = [];
let drow = word.split('').reverse().join('');
let regExp = new RegExp(${word.replace(/(\w)$/,'(?=$1)')}|${drow}, 'g');
s.replace(regExp, function(z, b) {
indexs.push(b)
});
return indexs;
}

[iLove-Coding]

        function findAnswer(word, s) {
            return [...getStr(word, s), ...getStr(reverseString(word), s)];
        }

        function getStr(word, s) {
            let s_copy = s;
            let arr = [];
            let temp = 0;
            while (true) {
                let index = s_copy.search(word);
                if (index !== -1) {
                    s_copy = s_copy.slice(index + word.length);
                    arr.push(temp + index);
                    temp = temp + index + word.length; //指针，开始在字符串首位置
                } else {
                    break;
                }
            }
            return arr;
        }

        function reverseString(str) {
            var newstr = str.split("").reverse().join("");
            return newstr;
        }

       findAnswer('abc', 'abcxabcbacc'); // [0, 4, 6]