USACO 2022 年一月美国计算机奥赛竞赛金奖组问题二——Farm Updates

Farmer John operates a collection of N farms (1≤N≤2·10^5), conveniently numbered 1…N. Initially, there are no roads connecting these farms to each-other, and each farm is actively producing milk.
Due to the dynamic nature of the economy, Farmer John needs to make changes to his farms according to a series of Q update operations (0≤Q≤2⋅10^5). Update operations come in three possible forms:
(D x) Deactivate an active farm x, so it no longer produces milk.
(A x y) Add a road between two active farms x and y.
(R e) Remove the eth road that was previously added (e=1 is the first road that was added).
A farm x that is actively producing milk, or that can reach another active farm via a series of roads, is called a "relevant" farm. For each farm x, please calculate the maximum i (0≤i≤Q) such that x is relevant after the i-th update.
INPUT FORMAT (input arrives from the terminal / stdin):
The first line of input contains N and Q. The next Q lines each contain an update of one of the following forms:
D x
A x y
R e
It is guaranteed that for updates of type R, e is at most the number of roads that have been added so far, and no two updates of type R have the same value of e.
OUTPUT FORMAT (print output to the terminal / stdout):
Please output N lines, each containing an integer in the range 0…Q.
SAMPLE INPUT:
5 9
A 1 2
A 2 3
D 1
D 3
A 2 4
D 2
R 2
R 1
R 3
SAMPLE OUTPUT:
7
8
6
9
9
In this example, roads are removed in the order (2,3),(1,2),(2,4).
Farm 1 is relevant just before (1,2) is removed.
Farm 2 is relevant just before (2,4) is removed.
Farm 3 is relevant just before (2,3) is removed.
Farms 4 and 5 are still active after all queries. Therefore they both stay relevant, and the output for both should be Q.
SCORING:
Tests 2 through 5 satisfy N≤103, Q≤2⋅103
Test cases 6 through 20 satisfy no additional constraints.