Can someone please explain to me why this 195043061 gives WA on test 7 while 195042850 got AC. The only difference is the first submission used Map while the second one used Set. Thanks in advance!

Given an array of n integers equal to zero. There are 3 type of queries:

1. Increase all elements from l to r by 1
2. Decrease all elements from l to r by 1
3. Count the number of zeros from l to r

Is there an efficient way to solve this problem in O(N log N), O(N sqrt(N)) or at least O(N log2 N)? Thank you in advance!

I've found a O(N log N) solution which I've implemented in 258E - Little Elephant and Tree, my submission: 226468052 (The STree namespace)