function longestCommonPrefix( strs ) {
    // write code here
    if(strs.length == 1) return strs[0];
    if(strs.includes("") || strs.length==0) return ""; //含有“”、数组长度为0
    let str = strs[0];
    for(let i = 0;i<str.length;i++){
        for(let j = 1;j<strs.length;j++){
            if(str[i] != strs[j][i]){
                return str.slice(0,i);
            }
        }
    }
    return str;
    
}
module.exports = {
    longestCommonPrefix : longestCommonPrefix
};