What does b contain?
a = [9 8 8 19 6 1 9 6 6 19]; b = unique(a);
b = [1 6 8 9]
b = [1 6 6 6 8 8 9 9 19 19]
b = [1 6 6 8 8 9]
b = [1 6 8 9 19]