var outtemp = ""; var outtemp2 = [];
longestWordChain(["abc","cba","ccc","cab","abca","acd","dabc","adc","c","ca"], "c");
function longestWordChain(keywords, startWord){
    var check = false;
    var chuoihientai = startWord;
    for(var i = 0;i < keywords.length;i++){
        if(startWord[startWord.length -1] == keywords[i][0]  && chuoihientai.split("-").indexOf(keywords[i]) == -1){
            dequytimchu(chuoihientai + "-" + keywords[i],keywords[i],keywords);
            check = true;
        }
    }
    if(!check){

        return startWord;
    }
    if(outtemp2.length == 1){

      return outtemp2[0];
    }
    var outtemp3 = [];var checkdodai = 0;
    for(var i = 0;i<outtemp2.length;i++){
      if(outtemp2[i].split("-").length >= checkdodai){
        checkdodai = outtemp2[i].split("-").length;
      }
    }
     for(var i = 0;i<outtemp2.length;i++){
      if(outtemp2[i].split("-").length == checkdodai){
        outtemp3.push(outtemp2[i]);
      }
    }
    outtemp3.sort();
    console.log(outtemp3);
    return outtemp3[0];
}
function dequytimchu(chuoihientai,tutieptheo,keywords){
    var check = false;
    for(var i = 0;i < keywords.length;i++){

        if(tutieptheo[tutieptheo.length -1] == keywords[i][0] && keywords[i] != tutieptheo && chuoihientai.split("-").indexOf(keywords[i]) == -1){
            dequytimchu(chuoihientai +"-"+keywords[i],keywords[i],keywords);
        }
    }
    if(outtemp.length <= chuoihientai.length){
            outtemp = chuoihientai;
            outtemp2.push(chuoihientai);
    }
}