So, I'm trying to solve the Multiset problem (https://mirror.codeforces.com/contest/1354/problem/D).
The memory limit is: 
but then I get a MLE although I'm only using 19MB (far from 28MB). 
What's the rationale behind this?
My code only uses the following data:
int n2 = 1048576;
int[] actualArray = new int[2 * n2];
so it should be about (2 * 1048576) * 4 bytes ~= 8MB. So, again, I'm far from 19MB. Any ideas why I get MLE?
The idea of my algorithm (https://mirror.codeforces.com/contest/1354/submission/82629303) is to use a segment tree. Where every leaf correspond to values from 1 to 10^6 (maximum n) and a leaf i contains how many times a value i exists in the initial array. Then, we sum up the leaves, etc.
Majority of the input is in a single line. Taking it all in (which you do using readLine) uses high amount of memory.
You need to read partial parts of the line. I don't have enough experience in Java to tell you how, but I do remember that this problem was very hostile to Java programmers.