mentor_sep_14.js

function onesInfection(matrix) {
  const rowSet = new Set()
  const colSet = new Set()
  for (let i = 0; i < matrix.length; i++) {
    for (let j = 0; j < matrix[i].length; j++) {
      if (matrix[i][j] == 1) {
        rowSet.add(i)
        colSet.add(j)
      }
    }
  }
  rowSet.forEach(row => transformRow(row, matrix))
  colSet.forEach(col => transformCol(col, matrix))
  return matrix
}

function transformRow(index, matrix) {
  matrix[index] = matrix[index].map(val => 1)
}

function transformCol(index, matrix) {
  matrix = matrix.map(row => row[index] = 1)
}

function covidSeating(row) {
  let emptySeats = 0;
  let res = 0
  for (let i = 0; i < row.length; i++) {
    if (row[i] == 0) {
      emptySeats += 1
      if (row[i - 1] && row[i - 1] == 1) emptySeats -= 1
      if (row[i + 1] && row[i + 1] == 1) {
        emptySeats -= 1
        res += Math.ceil(emptySeats / 2)
        emptySeats = 0
      }
    }
  }
  res += Math.ceil(emptySeats / 2)
  return res
}
console.log(covidSeating("10001")); // 1
// Can take place in the middle.

console.log(covidSeating("00101"));// 1
// Can take place on the left.

console.log(covidSeating("0"));// 1
// Can take one place.

console.log(covidSeating("000")); // 2
// Can take places on the left and on the right.

 console.log(covidSeating("100")); // 1
 // Can take place on the right.
 
 console.log(covidSeating("101")); // 0