binary-blob-challenge created by skiano - https://repl.it/@skiano/binary-blob-challenge

binary-blob-challenge.js

// SOLUTION 1

const getBlobBoundingBox1 = (blobString) => {
  blobString = blobString.trim()

  const width = (/\s/.exec(blobString) || {}).index
  const one = /1/g

  blobString = blobString.replace(/\s+/g, '')

  let top = Infinity
  let left = Infinity
  let right = 0
  let bottom = 0

  let match
  let i
  let x
  let y
  while ((match = one.exec(blobString)) !== null) {
    i = one.lastIndex - 1 // index of the 1
    x = i % width
    y = Math.floor(i / width)
    top = Math.min(top, y)
    left = Math.min(left, x)
    right = Math.max(right, x)
    bottom = Math.max(bottom, y)
  }

  return { top, left, right, bottom }
}

// SOLUTION 2

// the extra args just allo the instantiation to
// be grouped for common values
// i = current loop index
// x = x coordinate of loop index
// y = y coordinate of loop index
// t = top of bounding box
// l = left of bounding box
// r = right of bounding box
// b = bottom of bounding box

function getBlobBoundingBox2 (blob, i, x, y, t, l, r, b) {
  blob = blob.trim().replace(/\s+/g, '.')
  i = x = y = r = b = 0
  t = l = Infinity

  for (i; i < blob.length; i ++) {
    switch (blob[i]) {
      case '0':
        x++
        break

      case '1':
        t = t > y ? y : t
        l = l > x ? x : l
        r = r < x ? x : r
        b = b < y ? y : b
        x++
        break

      default:
        y += 1
        x = 0
    }
  }

  return { top: t, left: l, right: r, bottom: b }
}

const blobString = `
0000000000
0011100000
0011111000
0010001000
0011111000
0000101000
0000101000
0000111000
0000000000
0000000000
`

console.log(getBlobBoundingBox1(blobString))
console.log(getBlobBoundingBox2(blobString))