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leetcode : Longest Common Prefix : simple JavaScript solution

Posted on June 14, 2020

This is not the fastest solution’s by far, but I think that it is one of the more simple ones to understand.

var longestCommonPrefix = function(strs) {
    if(!strs[0]){return ""} //empty array case
    let lcp = "" //base case 
    //lcp can never be greater then first string 
    //so we can use it as the max length of our loop
    for(i=0;i<strs[0].length;i++){   
        let c=strs
            .map(s=>s[i])  //get all the i'th index letters 
            //get all the unique letters gathered in map
            .reduce((arr,char)=> arr.includes(char) ? arr : [...arr,char], [])
         if(c.length === 1){lcp += c[0]} //if unique letters == 1, keep looping
        else{break} //else loop is over
    }
    return lcp
};