DirectedCycle

java.lang.Object
- edu.princeton.cs.algs4.DirectedCycle

```
public class DirectedCycle
extends java.lang.Object
```
The DirectedCycle class represents a data type for determining whether a digraph has a directed cycle. The hasCycle operation determines whether the digraph has a simple directed cycle and, if so, the cycle operation returns one.
This implementation uses depth-first search. The constructor takes time proportional to V + E (in the worst case), where V is the number of vertices and E is the number of edges. Afterwards, the hasCycle operation takes constant time; the cycle operation takes time proportional to the length of the cycle.
See Topological to compute a topological order if the digraph is acyclic.
For additional documentation, see Section 4.2 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

构造器概要

构造器
构造器说明

DirectedCycle(Digraph G)
Determines whether the digraph G has a directed cycle and, if so, finds such a cycle.

方法概要

修饰符和类型	方法	说明
`java.lang.Iterable<java.lang.Integer>`	`cycle()`	Returns a directed cycle if the digraph has a directed cycle, and `null` otherwise.
`boolean`	`hasCycle()`	Does the digraph have a directed cycle?
`static void`	`main(java.lang.String[] args)`	Unit tests the `DirectedCycle` data type.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 构造器详细资料
  - DirectedCycle
```
public DirectedCycle(Digraph G)
```
    Determines whether the digraph G has a directed cycle and, if so, finds such a cycle.
    
    参数:
    
    G - the digraph
- 方法详细资料
  - hasCycle
```
public boolean hasCycle()
```
    Does the digraph have a directed cycle?
    
    返回:
    
    true if the digraph has a directed cycle, false otherwise
  - cycle
```
public java.lang.Iterable<java.lang.Integer> cycle()
```
    Returns a directed cycle if the digraph has a directed cycle, and null otherwise.
    
    返回:
    
    a directed cycle (as an iterable) if the digraph has a directed cycle, and null otherwise
  - main
```
public static void main(java.lang.String[] args)
```
    Unit tests the DirectedCycle data type.
    
    参数:
    
    args - the command-line arguments