questions used in the last interview.

interview.js

function recursive_mult(x, y) {
  if(y === 0 || x === 0) {
    return 0;
  }
  return x + recursive_mult(x, y-1);
}



console.log(recursive_mult(3,2));


//[[int]] -> int
function number_of_islands(matrix){
  var islands = 0;
  for(var i = 0; i< matrix.length; i++){
    for(var j = 0; j< matrix[0].length; j++){
      var value = matrix[i][j];
      if(value === 0){
        continue;
      } else {
        flood_fill(matrix, i,j);
        islands += 1;
      }
    }
  }
  return islands;
}

function flood_fill(matrix, i, j){
  if(matrix[i][j] === 0 || i<0 || j<0 || i>=matrix.length || j>=matrix[0].length){
    return;
  }
  matrix[i][j] = 0;
  flood_fill(matrix, i,j-1);
  flood_fill(matrix, i,  j+1);
  flood_fill(matrix, i+1,j);
  flood_fill(matrix, i-1,j);
}