P8436 [Template] Edge Biconnected Components

Given an undirected graph with $n$ vertices and $m$ edges, output the number of its edge biconnected components, and output each edge biconnected component.

The first line contains two integers $n$ and $m$. The next $m$ lines each contain two integers $u, v$, representing an undirected edge. **The graph is not guaranteed to be a simple graph. There may be multiple edges and self-loops in the graph.**

The first line contains an integer $x$, representing the number of edge biconnected components. The next $x$ lines: in each line, the first number is $a$, the number of vertices in this component, followed by $a$ numbers describing an edge biconnected component. You may output the edge biconnected components and the vertices within each component in any order.

**Explanation for Sample 4:**  Points with the same color belong to the same connected component. ------------ **Constraints:** For $100\%$ of the testdata, $1 \le n \le 5 \times 10^5$, $1 \le m \le 2 \times 10^6$. | subtask | $n$ | $m$ | score | | :----------: | :----------: | :----------: | :----------: | | $1$ | $1 \le n \le 100$ | $1 \le m \le 500$ | $25$ | | $2$ | $1 \le n \le 5000$ | $1 \le m \le 5 \times 10^4$ | $25$ | | $3$ | $1 \le n \le 2\times 10^5$ | $1 \le m \le 5\times 10^5$ | $25$ | | $4$ | $1 \le n \le 5 \times10 ^ 5$ | $1 \le m \le 2 \times 10^6$ | $25$ | ### Data Updates - $2022/7/14$ testdata strengthened. - $2022/11/26$ added $10$ new smaller test groups ($1 \le n, m \le 10$) to make debugging easier. - $2022/12/31$ reorganized the $subtask$ setup and added several groups of extreme testdata. - $2023/1/1$ found issues in the newly added testdata from yesterday, and fixed them. ------------ This problem is not strict on time limits. Both the time limit and memory limit are set high, so any correct solution can pass. ------------ Surprise: after getting AC, remember to place your mouse over the test points to see the feedback information. There is a surprise. Translated by ChatGPT 5