Twitter Code Interview

index.js

const CHUNKS = 3;

/** @paran {array} input */
function mostFrecuentHistory(input) {
  const globalCounter = {}
  input.forEach(arr => {
    arr.forEach(log => {
      if (!globalCounter[log])  {
        globalCounter[log] = 0;
      }
      globalCounter[log]++;
      });
    });
  let maxValue = -1;
  let maxKey = -1;
  Object.keys(globalCounter).forEach(key => {
    if (maxValue < globalCounter[key]) {
      maxKey = key;
      maxValue = globalCounter[key];
    }
  });
  console.log("LONG: ", maxKey, "Times: ", maxValue);
}

/** @paran {string} input, @returns {object} */
function splitIntoUsers(input) {
  const tweets = input.split(' ');
  const tweetsByUser = {}
  for (let i = 0; i < tweets.length; i++) {
    const tweet = tweets[i].split(',');
    const username = tweet[0];
    const tweet_id = tweet[1];
    if (!tweetsByUser[username]) {
      tweetsByUser[username] = [];
    }
    tweetsByUser[username].push(tweet_id);
  }
  return tweetsByUser;
} 
/** @paran {array} input, @returns {array} */
function findHistoryForInput(tweets) {
  let globaCounter = []; 
  let temporalChunk = [];  
  let firstTime = false;
  for (let i = 0; i < tweets.length; i++) {
      const tweet_id = tweets[i];
      if (CHUNKS > i) {
          // Is one of the first 3 elments, create chunk (*)
          temporalChunk.push(tweet_id);
      } else {
        // (*) First iteration
        if (temporalChunk.length == CHUNKS && firstTime == false) {
          globaCounter.push(temporalChunk.join(" "));
          firstTime = true;
        }
        // Start look for the last 2 (CHUNKS - 1)
        temporalChunk = [ temporalChunk[CHUNKS - 2], temporalChunk[CHUNKS - 1], tweet_id]; 
        globaCounter.push(temporalChunk.join(" "));
      }
  }
  return globaCounter;
}

const input = "@Biz,T1 @Jack,T7 @Biz,T2 @Jack,T8 @Biz,T3 @Biz,T3 @Biz,T2 @Biz,T1 @Biz,T2 @Jack,T9 @Jack,T7 @Jack,T8 @Jack,T9 @Biz,T3 @Biz,T7 @Biz,T8 @Biz,T9";

function main() {
  // Split into user.
  const userLogs = splitIntoUsers(input);
  // Get the history by user
  const historyByUser = Object.keys(userLogs).map(key => {
    const dataByUser = userLogs[key];
    return findHistoryForInput(dataByUser);
  });
  // Get the most frequent history
  mostFrecuentHistory(historyByUser);
}

main();

Taken notes