package com.coderising.array;
import com.*;
public class ArrayUtil {
/**
* 给定一个整形数组a , 对该数组的值进行置换
例如: a = [7, 9 , 30, 3] , 置换后为 [3, 30, 9,7]
如果 a = [7, 9, 30, 3, 4] , 置换后为 [4,3, 30 , 9,7]
* @param origin
* @return
*/
public void reverseArray(int[] origin){
if (1 == origin.length || 0 == origin.length)
{
return;
}
int temp = 0;
for (int i = 0; i < origin.length / 2; i++)
{
temp = origin[i];
origin[i] = origin[origin.length - 1 - i];
origin[origin.length - 1 - i] = temp;
}
}
/**
* 现在有如下的一个数组: int oldArr[]={1,3,4,5,0,0,6,6,0,5,4,7,6,7,0,5}
* 要求将以上数组中值为0的项去掉,将不为0的值存入一个新的数组,生成的新数组为:
* {1,3,4,5,6,6,5,4,7,6,7,5}
* @param oldArray
* @return
*/
public Integer[] removeZero(int[] oldArray){
com.coding.basic.ArrayList blist = new com.coding.basic.ArrayList();
//int j = 0;
for(int i = 0; i < oldArray.length; i++)
{
if (0 != oldArray[i])
{
blist.add(oldArray[i]);
}
}
Object[] newArray = blist.ToArray();
return (Integer[])newArray;
}
/**
* 给定两个已经排序好的整形数组, a1和a2 , 创建一个新的数组a3, 使得a3 包含a1和a2 的所有元素, 并且仍然是有序的
* 例如 a1 = [3, 5, 7,8] a2 = [4, 5, 6,7] 则 a3 为[3,4,5,6,7,8] , 注意: 已经消除了重复
* @param array1
* @param array2
* @return
*/
public Integer[] merge(int[] array1, int[] array2){
com.coding.basic.ArrayList blist = new com.coding.basic.ArrayList();
int i = 0;
for (i = 0; i < array1.length; i++)
{
blist.add(array1[0]);
}
for(i = 0; i < array2.length; i++)
{
for (int j = 0; j < blist.size(); j ++)
{
if (array2[i] >= (int)blist.get(j + 1))
{
if (array2[i] == (int)blist.get(j + 1))
{
break;
}
//已经到最后了
if (j == blist.size() - 1)
{
if (array2[i] == (int)blist.get(j + 1))
{
break;
}
else
{
blist.add(j + 1, array2[i]);
break;
}
}
else
{
if (array2[i] <= (int)blist.get(j + 2))
{
if (array2[i] == (int)blist.get(j + 2))
{
break;
}
else
{
blist.add(j + 1, array2[i]);
break;
}
}
}
}
else
{
if (j == 0)
{
blist.add(j + 1, array2[i]);
break;
}
else
{
continue;
}
}
}
}
return (Integer[]) blist.ToArray();
}
/**
* 把一个已经存满数据的数组 oldArray的容量进行扩展, 扩展后的新数据大小为oldArray.length + size
* 注意,老数组的元素在新数组中需要保持
* 例如 oldArray = [2,3,6] , size = 3,则返回的新数组为
* [2,3,6,0,0,0]
* @param oldArray
* @param size
* @return
*/
public int[] grow(int [] oldArray, int size){
int[] NewArray = new int[oldArray.length + size];
for(int i = 0; i < NewArray.length; i++)
{
if (i < oldArray.length) {
NewArray[i] = oldArray[i];
}
else
{
NewArray[i] = 0;
}
}
return NewArray;
}
/**
* 斐波那契数列为:1,1,2,3,5,8,13,21...... ,给定一个最大值, 返回小于该值的数列
* 例如, max = 15 , 则返回的数组应该为 [1,1,2,3,5,8,13]
* max = 1, 则返回空数组 []
* @param max
* @return
*/
public Integer[] fibonacci(int max){
com.coding.basic.ArrayList result = new com.coding.basic.ArrayList();
int i = 0;
int TempMax = 0;
while (true)
{
TempMax = CaculateFibonacci(i++);
if (TempMax <= max)
{
result.add(TempMax);
continue;
}
else
{
break;
}
}
return (Integer[])result.ToArray();
}
public int CaculateFibonacci(int i)
{
if (1 == i)
return 1;
else if (2 == i)
return 1;
else
return CaculateFibonacci(i - 1) + CaculateFibonacci(i - 2);
}
/**
* 返回小于给定最大值max的所有素数数组
* 例如max = 23, 返回的数组为[2,3,5,7,11,13,17,19]
* @param max
* @return
*/
public Integer[] getPrimes(int max){
com.coding.basic.ArrayList result = new com.coding.basic.ArrayList();
for(int i = 2; i < max; i ++)
{
if(CaculatePrimes(i))
{
result.add(i);
}
}
return (Integer[])result.ToArray();
}
//计算素数函数 算法好像不高明啊!
public boolean CaculatePrimes(int Num)
{
for (int i = 2; i < Math.sqrt(Num); i++)
{
if (Num % i == 0)
{
return false;
}
}
return true;
}
/**
* 所谓“完数”, 是指这个数恰好等于它的因子之和,例如6=1+2+3
* 给定一个最大值max, 返回一个数组, 数组中是小于max 的所有完数
* @param max
* @return
*/
public Integer[] getPerfectNumbers(int max){
com.coding.basic.ArrayList result = new com.coding.basic.ArrayList();
for (int i = 6; i < max; i++)
{
if (IsPerfectNumber(i))
{
result.add(i);
}
}
return (Integer[])result.ToArray();
}
//计算所有的因子之和 算法并不高明啊!
public boolean IsPerfectNumber(int Num)
{
int temp = 0;
for (int i = 1; i < Num; i++)
{
if (Num % i == 0)
{
temp += i;
}
}
if (temp == Num)
{
return true;
}
else
{
return false;
}
}
/**
* 用seperator 把数组 array给连接起来
* 例如array= [3,8,9], seperator = "-"
* 则返回值为"3-8-9"
* @param array
* @param
* @return
*/
public String join(int[] array, String seperator){
String result = "";
for (int i = 0; i < array.length - 1; i++)
{
result += Integer.toString(array[i])+ seperator;
}
result += Integer.toString(array[array.length]);
return result;
}
}