P4146 Sequence Terminator

There are many problems online where, given a sequence, you need to support several operations: A, B, C, D. Then you see another problem: again a sequence with operations to support: D, C, B, A. Especially someone here, when making a mock exam, even made one like this. Honestly, there is not much technical content in that... So I will also make one. My goal is to let everyone have a “library” to rely on when solving such problems in the future, nothing else. Let’s call this problem Sequence Terminator.

Given a sequence of length $N$, each element is an integer (trivial). You need to support the following three operations: 1. Add $V$ to every number in the interval $[L,R]$. 2. Reverse the interval $[L,R]$, for example, `1 2 3 4` becomes `4 3 2 1`. 3. Query the maximum value in the interval $[L,R]$. Initially, all elements are $0$.

The first line contains two integers $N，M$. $M$ is the number of operations. The next $M$ lines each contain up to four integers, in order: $K，L，R，V$. $K$ indicates the operation type. If it is not the $1$st operation, then only two numbers follow $K$.

For each operation of type $3$, output the correct answer.

$1\le N \le 50000$，$1\le M \le 100000$，$|V| \leq 1000$。 Translated by ChatGPT 5