leetcode5-最長の部分文字列を見つける

const str2 = '1111waabbibiiomomomomomo'
const str1 = '11111111111111111111111'
const str = 'abcbcajkljljljlnninino'

/**
 *   最长回文子串
 */
function longestSubStr(str) {
    
    
    let i = 0;j = str.length -1;
    str = str.split('')
    let result = []
    while(i <j) {
    
    
        if(str[i] === str[j]) {
    
    
            i ++ ,
            j --
            result.push(str[i])
        } else {
    
    
            i ++
        }
    }
    if(result.length === 1) {
    
    
        return null
    }
    return [...result,...result].join('');
}


const res = longestSubStr(str2)
console.log(res);