y(end)=0.9279 is equal to x(end)=0.9288 at t=33
0.9729 is smaller than any x value, and is closest to x(18) which is 0.9280.
y(4)=0.9712 is almost equal equal to x(5)=0.9735 at t=5
0.9712 is closer to x(25) = 0.9718
The descriptive part about "near to x values" leads to this code:
plot(1:length(x),x,'r',interp1(x, 1:length(x), y, 'nearest', 'extrap'),y,'g.-')
which has each y value being drawn at the t value that corresponds to the x value that is closest to the y value.
Your rules about what is near enough do not appear to be well defined.
