4 The Decision Boundary for INN (i.e., 1-Nearest Neighbors Classifier) (20 points) For each of the following 4 figures, we are given a few data points in the 2-D space, each of which is labeled as either '+' or '-'. Draw the decision boundary for 1NN, assuming we use L (Euclidean) distance. + + (a) + + (b) + + + (c) (d) Figure 3: Problem 4: Training Data Set for INN Classifiers + +