SOURCE

const reverseStr = (str) => {
    let arr = str.split('')
    return arr.reverse().join('')
}
const reverseStr2 = (str)=> {
    let a = Math.abs(str)
    let num = 0;
    while(a!==0) {
        num = (a%10)+num*10
        a = Math.floor(a/10)
    }
    return num
}


const isCon = (c,d) => {
    const cc= c.split('')
    const dd= d.split('')
    cc.sort((a,b) => {
        return a.charCodeAt() - b.charCodeAt()
    })
    dd.sort((a,b) => {
        return a.charCodeAt() - b.charCodeAt()
    })
    if(cc.join('') === dd.join('')) {
        return true
    }else {
        return false
    }
}
// console.log(isCon('anagram', 'nagaram'))

const reverseStr3 = (arr) => {
    for(let i =0;i<arr.length/2;i++) {
        [arr[i], arr[arr.length-i-1]] = [arr[arr.length-i-1], arr[i]]
    }
    // console.log(arr)
    return arr
}
reverseStr3(["o","l","l","e","h"])

const findOnly = (str) => {
    let hash = {}
    for(let i=0;i<str.length;i++) {
        hash[str[i]]?hash[str[i]]+=1:hash[str[i]]=1
    }
    for(let i=0;i<str.length;i++) {
        if(hash[str[i]]===1) {
            // console.log(i)
            return i
        }
    }
}
findOnly('loveleetcode')

const findPos = (haystack, needle) => {
    const hayLen = haystack.length
    const neeLen = needle.length
    if(neeLen>hayLen) {
        return -1
    }else if(neeLen===hayLen) {
        return haystack===needle?0:-1
    }else {
        for(let i=0;i<hayLen;i++) {
            
            if(haystack[i] !== needle[0]) {
                continue
            }
            console.log(haystack.substring(i,i+neeLen))
            if(haystack.substring(i,i+neeLen) === needle) {
                console.log(i)
                return i
            }
        }
    }
    return -1
}
findPos('hello world','ll')

const findLongSame = (arr) => {
    function findSame(a, b) {
        let i = 0
        while(i<a.length && i<b.length && a.charAt(i) == b.charAt(i)) {
            i++
        }
        return i>0?a.substring(0, i):''
    }
    let preSame = arr[0];
    for(let i= 1;i<arr.length;i++) {
        preSame = findSame(preSame,arr[i])
    }
    console.log(preSame)
    return preSame;
}

findLongSame(["flower","flow","flight"])