Merge pull request #18 from wa122as/master

mini Struts 和Arrayutil

.gitignore

@@ -1 +1,28 @@
+# Package Files #
+*.jar
+*.war
+*.ear
+
+*.iml
+*.idea
+
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+#ide config
+.metadata
+.recommenders
+.idea
+
+
+#macOS
+.DS_Store
+
+.idea/
+*.iml
+rebel.*
+.rebel.*
+
+target
 

group15/1521_653895972/.gitignore

@@ -0,0 +1,3 @@
+/out
+.idea
+*.iml

group15/1521_653895972/src/com/coding/coderising/array/ArrayUtilTest.java

@@ -0,0 +1,73 @@
+package com.coding.coderising.array;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+
+/**
+ * Created by wanc on 2017/2/28.
+ */
+public class ArrayUtilTest {
+
+    @Test
+    public void testReverseArray() throws Exception {
+        int[] arr = {7, 9, 30, 3};
+        SimpleArrayUtil.reverseArray(arr);
+        System.out.println(Arrays.toString(arr));
+        System.out.println("----------------------置换 end-----------------------------");
+    }
+
+
+    @Test
+    public void testRemoveZero() throws Exception {
+        int oldArr[] = {1, 3, 4, 5, 0, 0, 6, 6, 0, 5, 4, 7, 6, 7, 0, 5};
+        int newArr[] = SimpleArrayUtil.removeZero(oldArr);
+        System.out.println(Arrays.toString(newArr));
+        System.out.println("----------------------去零 end-----------------------------");
+    }
+
+    @Test
+    public void testMerge() throws Exception {
+        int arr1[] = {3, 5, 7, 8};
+        int arr2[] = {4, 5, 6, 7};
+        int arr3[] = SimpleArrayUtil.merge(arr1, arr2);
+        System.out.println(Arrays.toString(arr3));
+        System.out.println("----------------------merge end-----------------------------");
+    }
+
+    @Test
+    public void testGrow() throws Exception {
+        int arr1[] = {3, 5, 7, 8};
+        int[] newArr = SimpleArrayUtil.grow(arr1, 3);
+        System.out.println(Arrays.toString(newArr));
+        System.out.println("----------------------扩展 end-----------------------------");
+    }
+
+    @Test
+    public void testFibonacci() throws Exception {
+        int[] arr = SimpleArrayUtil.fibonacci(15);
+        System.out.println(Arrays.toString(arr));
+        System.out.println("----------------------斐波那契 end-----------------------------");
+    }
+
+    @Test
+    public void testGetPrimes() throws Exception {
+        int[] arr = SimpleArrayUtil.getPrimes(23);
+        System.out.println(Arrays.toString(arr));
+        System.out.println("----------------------素数 end-----------------------------");
+    }
+
+    @Test
+    public void testGetPerfectNumbers() throws Exception {
+        int[] newArr = SimpleArrayUtil.getPerfectNumbers(50);
+        System.out.println(Arrays.toString(newArr));
+        System.out.println("----------------------完数 end-----------------------------");
+    }
+
+    @Test
+    public void testJoin() throws Exception {
+        int arr1[] = {3, 5, 7, 8};
+        System.out.println(SimpleArrayUtil.join(arr1, "-"));
+        System.out.println("----------------------Join end-----------------------------");
+    }
+}

group15/1521_653895972/src/com/coding/coderising/array/SimpleArrayUtil.java

@@ -0,0 +1,250 @@
+package com.coding.coderising.array;
+
+public class SimpleArrayUtil {
+
+    private static void checkNull(int[] array) {
+        if (array == null)
+            throw new NullPointerException("array is null");
+    }
+
+    /**
+     * 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 static void reverseArray(int[] origin) {
+        checkNull(origin);
+        int i = 0;
+        for (int j = origin.length - 1; j > i; ++i) {
+            int tmp = origin[i];
+            origin[i] = origin[j];
+            origin[j] = tmp;
+            --j;
+        }
+    }
+
+    /**
+     * 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 static int[] removeZero(int[] oldArray) {
+        checkNull(oldArray);
+        if (0 == oldArray.length)
+            return oldArray;
+        int[] temp = new int[oldArray.length];
+        int index = 0;
+        for (int i = 0; i < oldArray.length; i++) {
+            if (0 != oldArray[i]) {
+                temp[index++] = oldArray[i];
+            }
+        }
+        int[] tem2 = new int[index];
+
+        System.arraycopy(temp, 0, tem2, 0, Math.min(oldArray.length, index));
+        return tem2;
+    }
+
+    /**
+     * 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 static int[] merge(int[] array1, int[] array2) {
+        if (array1 == null && array2 == null)
+            return null;
+        if (array1.length == 0)
+            return array2.clone();
+        if (array2.length == 0)
+            return array1.clone();
+        //判断排序方向
+        boolean sort = array1[0] < array1[array1.length - 1];
+        //去重
+        for (int i = 0; i < array2.length; i++) {
+            boolean flag = true;
+            for (int j = 0; j < array1.length; j++) {
+                if (array2[i] == array1[j]) {
+                    flag = false;
+                    break;
+                }
+            }
+            if (flag) {
+                //扩容
+                array1 = grow(array1, 1);
+                array1[array1.length - 1] = array2[i];
+            }
+        }
+        //排序
+        if (sort) {//小到大
+            int tmp;
+            //冒泡排序
+            for (int i = 0; i < array1.length; i++) {
+                for (int j = i + 1; j < array1.length; j++) {
+                    if (array1[i] > array1[j]) {
+                        tmp = array1[i];
+                        array1[i] = array1[j];
+                        array1[j] = tmp;
+                    }
+                }
+            }
+        } else {//大到小
+            int tmp;
+            //冒泡排序
+            for (int i = 0; i < array1.length; i++) {
+                for (int j = i + 1; j < array1.length; j++) {
+                    if (array1[i] < array1[j]) {
+                        tmp = array1[i];
+                        array1[i] = array1[j];
+                        array1[j] = tmp;
+                    }
+                }
+            }
+        }
+        return array1;
+    }
+
+    /**
+     * 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 static int[] grow(int[] oldArray, int size) {
+        int[] newArr = new int[oldArray.length + size];
+        System.arraycopy(oldArray, 0, newArr, 0, oldArray.length);
+        return newArr;
+    }
+
+    /**
+     * 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 static int[] fibonacci(int max) {
+        int[] arr = new int[]{};
+        int i = 1;
+        while (true) {
+            int a = fb(i);
+            if (a > 15)
+                break;
+            //扩容
+            arr = grow(arr, 1);
+            arr[i - 1] = a;
+            i++;
+        }
+        return arr;
+    }
+
+    /**
+     * 获取斐波那契数
+     * F(0)=1，F(1)=1, F(n)=F(n-1)+F(n-2)（n>=2，n∈N*）
+     */
+    public static int fb(int i) {
+        i = i < 1 ? 1 : i;
+        if (i == 1 || i == 2) {
+            return 1;
+        }
+        return fb(i - 1) + fb(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 static int[] getPrimes(int max) {
+        int[] arr = new int[]{2};
+        if (max < 1) throw new IllegalArgumentException("不是大于1的自然数");
+        int j = 1;
+        for (int n = 3; n < max; n++) {
+            int k = 2;
+            while (n > k) {
+                if (n % k == 0)
+                    break;
+                k++;
+            }
+            //扩容
+            arr = grow(arr, 1);
+            arr[j++] = n;
+        }
+        return arr;
+    }
+
+
+    /**
+     * 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 static int[] getPerfectNumbers(int max) {
+        int[] arr = new int[0];
+        int a = 0;
+        for (int i = 1; i < max; i++) {
+            if (isPerfect(i)) {
+                //扩容
+                arr = grow(arr, 1);
+                arr[a++] = i;
+            }
+        }
+        return arr;
+    }
+
+    //判断 “完数”
+    public static boolean isPerfect(int max) {
+        int i = 1;
+        int n = 0;
+        while (i < max) {
+            if (max % i == 0) {
+                n += i;
+            }
+            i++;
+        }
+        if (n == max)
+            return true;
+        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 seperator
+     * @return
+     */
+    public static String join(int[] array, String seperator) {
+        if (array == null)
+            return null;
+        String s = "";
+        for (int i = 0; i < array.length; i++) {
+            s += array[i];
+            if (i != array.length - 1)
+                s += seperator;
+        }
+        return s;
+    }
+
+
+}