W2D1_Tutorial 4 coding problem in exercise 4

dear all, I have a problem in W2D1 solving Exercise 4, Tutorial 4, it asks for implementation of binary decision matrix by making the position of the mean (the position of the gaussian peak) =1 for each trial (row). I tried writing code in my own way like the same solution of tutorial 3, that’s by searching maximum value of posterior matrix in each row (making argmax of each row = 1), while the provided solution searched for the minimum value of x - mean and set it to 1.
I see both solution should outcome the same result, but can’t know why they look different?