You live in the city of Cartesia where all roads are laid out in a perfect grid. You arrived ten minutes too early to an appointment, so you decided to take the opportunity to go for a short walk. The city provides its citizens with a Walk Generating App on their phones -- everytime you press the button it sends you an array of one-letter string…

Take a Ten Minute Walk

function isValidWalk(walk) {
  var dx = 0
  var dy = 0
  var dt = walk.length
  
  for (var i = 0; i < walk.length; i++) {
    switch (walk[i]) {
      case 'n': dy--; break
      case 's': dy++; break
      case 'w': dx--; break
      case 'e': dx++; break
    }
  }
  
  return dt === 10 && dx === 0 && dy === 0
}