display-pages.js

/**
 * Display Pages
 * 
 * Given you a list of the following strings, display them in pages.
 * 
 * The input has the following format: "host_id,listing_id,score,city", 
 * make sure you print the same host_id record once on the same page
 * 
 * Input:
 * [
 *   "1,28,300.1,SanFrancisco",
     "4,5,209.1,SanFrancisco",
     "20,7,208.1,SanFrancisco",
     "23,8,207.1,SanFrancisco",
     "16,10,206.1,Oakland",
     "1,16,205.1,SanFrancisco",
     "6,29,204.1,SanFrancisco",
     "7,20,203.1,SanFrancisco",
     "8,21,202.1,SanFrancisco",
     "2,18,201.1,SanFrancisco",
     "2,30,200.1,SanFrancisco",
     "15,27,109.1,Oakland",
     "10,13,108.1,Oakland",
     "11,26,107.1,Oakland",
     "12,9,106.1,Oakland",
     "13,1,105.1,Oakland",
     "22,17,104.1,Oakland",
     "1,2,103.1,Oakland",
     "28,24,102.1,Oakland",
     "18,14,11.1,SanJose",
     "6,25,10.1,Oakland",
     "19,15,9.1,SanJose",
     "3,19,8.1,SanJose",
     "3,11,7.1,Oakland",
     "27,12,6.1,Oakland",
     "1,3,5.1,Oakland",
     "25,4,4.1,SanJose",
     "5,6,3.1,SanJose",
     "29,22,2.1,SanJose",
     "30,23,1.1,SanJose"
 * ]
 * Page size: 12
 *
 * Output:
 * 
 * Page 1
 * 1,28,300.1,SanFrancisco
 * 4,5,209.1,SanFrancisco
 * 20,7,208.1,SanFrancisco
 * 23,8,207.1,SanFrancisco
 * 16,10,206.1,Oakland
 * 6,29,204.1,SanFrancisco
 * 7,20,203.1,SanFrancisco
 * 8,21,202.1,SanFrancisco
 * 2,18,201.1,SanFrancisco
 * 15,27,109.1,Oakland
 * 10,13,108.1,Oakland
 * 11,26,107.1,Oakland
 * 
 * Page 2
 * 1,16,205.1,SanFrancisco
 * 2,30,200.1,SanFrancisco
 * 12,9,106.1,Oakland
 * 13,1,105.1,Oakland
 * 22,17,104.1,Oakland
 * 28,24,102.1,Oakland
 * 18,14,11.1,SanJose
 * 6,25,10.1,Oakland
 * 19,15,9.1,SanJose
 * 3,19,8.1,SanJose
 * 27,12,6.1,Oakland
 * 25,4,4.1,SanJose
 * 
 * Page 3
 * 1,2,103.1,Oakland
 * 3,11,7.1,Oakland
 * 5,6,3.1,SanJose
 * 29,22,2.1,SanJose
 * 30,23,1.1,SanJose
 * 
 * Page 4
 * 1,3,5.1,Oakland
 */

/**
 * Print the pages by page size
 * @param {string[]} input
 * @return {string[][]}
 */
const displayPages = (input, pageSize) => {
  if (!input || input.length === 0) {
    return [];
  }

  const pages = [];
  const visited = new Set();
  const deleted = new Set();
  let page = [];
  let i = 0;

  while (input.length > 0) {
    const curr = input[i];
    const hostId = curr.split(',')[0];

    // Should we add the record to the current page
    if (!visited.has(hostId)) {
      page.push(curr);
      visited.add(hostId);
      deleted.add(i);
    }

    // Is current page full
    if (visited.size === pageSize || i === input.length - 1) {
      pages.push(page);
      // Reset
      input = input.filter((str, index) => !deleted.has(index));
      deleted.clear();
      visited.clear();
      page = [];
      i = 0;
    } else {
      i++;
    }
  }

  return pages;
};

export { displayPages };