org.nutz.lang

Class Maths

java.lang.Object

org.nutz.lang.Maths

public abstract class Maths
extends Object

A group of helper functions to counting some ...

Author:

zozoh(zozohtnt@gmail.com), pw

Constructor Summary

Constructors

Constructor and Description
Maths()

Method Summary

Modifier and Type	Method and Description
static int	bit(String s) Convert a binary string to a integer
static int	extract(int bs, int low, int high) Get part of one integer as a new integer
static boolean	isMask(int bs, int mask) Test current bit is match the given mask at least one bit or not.
static boolean	isMaskAll(int bs, int mask) Test current bit is all match the give mask.
static boolean	isNoMask(int bs, int mask)
static int	max(int... nums) 返回最大的一个
static int	min(int... nums) 返回最小的一个
static String[]	permutation(char... arr) 获得字符数组的全排列
static String[]	permutation(int length, char... arr) 按照指定长度, 获得字符数组的全排列

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Maths

public Maths()

Method Detail

max

public static int max(int... nums)

返回最大的一个

Parameters:

nums - 需要比较的数组

Returns:

最大值

min

public static int min(int... nums)

返回最小的一个

Parameters:

nums - 需要比较的数组

Returns:

最小值

bit

public static int bit(String s)

Convert a binary string to a integer

Parameters:

s - binary string

Returns:

integer

isMask

public static boolean isMask(int bs,
                             int mask)

Test current bit is match the given mask at least one bit or not.

Parameters:

bs - integer, bit map

mask - another bit map

Returns:

if one of bit value is '1' in mask, and it is also is '1' in bs return true, else false

isNoMask

public static boolean isNoMask(int bs,
                               int mask)

isMaskAll

public static boolean isMaskAll(int bs,
                                int mask)

Test current bit is all match the give mask.

Parameters:

bs - integer, bit map

mask - another bit map

Returns:

if all bit value is '1' in mask, and it is also is '1' in bs return true, else false

extract

public static int extract(int bs,
                          int low,
                          int high)

Get part of one integer as a new integer

Parameters:

bs - original integer

low - the low bit position (inclusive), 0 base

high - the hight bit position (exclusive), 0 base

Returns:

new integer

permutation

public static String[] permutation(char... arr)

获得字符数组的全排列

Parameters:

arr - 字符数组

Returns:

全排列

permutation

public static String[] permutation(int length,
                                   char... arr)

按照指定长度, 获得字符数组的全排列

Parameters:

arr - 字符数组

Returns:

全排列