polyFeatures  <- function(X, p) {
  
  #   Maps X (1D vector) into the p-th power
  #
  #   X_poly <- polyFeatures(X, p) takes a data matrix X (size m x 1) and
  #   maps each example into its polynomial features where
  #   X_poly[i, ] <- [X[i] X[i].^2 X[i].^3 ...  X[i].^p]
  #
  
  # You need to return the following variables correctly.
  X_poly <- matrix(0, nrow = ifelse(!is.null(nrow(X)), nrow(X), length(X)), ncol = p)
  
  # ======================= YOUR CODE HERE =======================
  # Instructions: Given a vector X, return a matrix X_poly where the p-th
  #               column of X contains the values of X to the p-th power.
  #
  #
  
  
  
  # ==============================================================
  return(X_poly)
}