Let's draw a vertical line $x = -\infty$ mentally and start moving this line to the right.

In the course of its movement, this line will meet with segments, and at each time a segmentintersect with our line it intersects in exactly one point (we will assume that there are no vertical segments).

In the course of its movement, this line will meet with segments, and at each time a segmentintersects with our line it intersects in exactly one point (we will assume that there are no vertical segments).

<divstyle="text-align:center;">

<imgsrc="sweep_line_1.png"alt="sweep line and line segment intersection">

The required topological ordering will be the vertices sorted in descending order of exit time.

* Check whether a given graph is acyclic and find cycles in a graph. (As mentionedabove by counting back edges in every connected components).

* Check whether a given graph is acyclic and find cycles in a graph. (As mentionedbelow by counting back edges in every connected components).

* Find strongly connected components in a directed graph:

<spanclass="contributors-text">Contributors:</span>

<ulclass="contributors"data-bi-name="contributors">

{%- for user in contribs -%}

<li><ahref="{{ user.url }}"title="{{ user.name }}"data-bi-name="contributorprofile"target="_blank">{{ user.name }}</a> ({{user.contribution}}%)</li>

<li><ahref="{{ user.url }}"title="{{ user.name }}"data-bi-name="contributorprofile"target="_blank">{{ user.name }}</a> ({{user.contribution|round(2)}}%)</li>

{%- endfor -%}