data = load('data.txt');
X = data(:, [1, 2]); y = data(:, 3);
pos = find(y == 1); neg = find(y == 0);
plot(X(pos, 1), X(pos, 2), "+k", X(neg, 1), X(neg, 2), "ok", "MarkerFaceColor", "y", "MarkerSize", 7, "LineWidth", 2);
