字符串中连续最多的字符&次数

　　双层for循环

const repeatStrAndNumsByDoubleLoop = (str = 'aabbbcccddeeefffff') => {
    const res = {
        char: '',
        len: 0
    }
    const { length } = str
    for(let i = 0; i < length; i++){
        let charLen = 1
        const curValue = str[i]
        for(let j = i + 1; j < length; j++){
            const nextValue = str[j]
            if(curValue === nextValue){
                charLen += 1
            }
            if(curValue !== nextValue || j === length - 1){
                if(charLen > res.len){
                    res.char = curValue
                    res.len = charLen
                }
                i = j - 1 // 进行跳步 减少时间复杂度
                break
            }
        }
    }
    return res
}

　　双指针　

const repeatStrAndNumsByDoublePointer = (str = 'aabbbcccddeeefffff') => {
    const res = {
        char: '',
        len: 0
    }
    const { length } = str
    if (!length) {
        return res
    }
    if(length === 1){
        return {
            char:str,
            len: 1
        }
    }
    let fixedIndex = 0
    let len = 1
    for(let i = 1; i < length; i++){
        const value = str[i]
        if(value === str[fixedIndex]){
            len++
        }
        if(value !== str[fixedIndex] || i === length - 1) {
            if(len > res.len){
                res.len = len
                res.char = str[i - 1]
            }
            fixedIndex = i
            len = 1
        }
    }
    return res
}