ThreeSumFast

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

```
public class ThreeSumFast
extends java.lang.Object
```
The ThreeSumFast class provides static methods for counting and printing the number of triples in an array of distinct integers that sum to 0 (ignoring integer overflow).
This implementation uses sorting and binary search and takes time proportional to n^2 log n, where n is the number of integers.
For additional documentation, see Section 1.4 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

方法概要

修饰符和类型	方法	说明
`static int`	`count(int[] a)`	Returns the number of triples (i, j, k) with `i < j < k` such that `a[i] + a[j] + a[k] == 0`.
`static void`	`main(java.lang.String[] args)`	Reads in a sequence of distinct integers from a file, specified as a command-line argument; counts the number of triples sum to exactly zero; prints out the time to perform the computation.
`static void`	`printAll(int[] a)`	Prints to standard output the (i, j, k) with `i < j < k` such that `a[i] + a[j] + a[k] == 0`.

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

- 方法详细资料
  - printAll
```
public static void printAll(int[] a)
```
    Prints to standard output the (i, j, k) with i < j < k such that a[i] + a[j] + a[k] == 0.
    
    参数:
    
    a - the array of integers
    
    抛出:
    
    java.lang.IllegalArgumentException - if the array contains duplicate integers
  - count
```
public static int count(int[] a)
```
    Returns the number of triples (i, j, k) with i < j < k such that a[i] + a[j] + a[k] == 0.
    
    参数:
    
    a - the array of integers
    
    返回:
    
    the number of triples (i, j, k) with i < j < k such that a[i] + a[j] + a[k] == 0
  - main
```
public static void main(java.lang.String[] args)
```
    Reads in a sequence of distinct integers from a file, specified as a command-line argument; counts the number of triples sum to exactly zero; prints out the time to perform the computation.
    
    参数:
    
    args - the command-line arguments