diff --git a/javaturorial.iml b/javaturorial.iml
index 4e3316b..175c741 100644
--- a/javaturorial.iml
+++ b/javaturorial.iml
@@ -10,7 +10,7 @@
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="library" scope="TEST" name="Maven: junit:junit:4.12" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: junit:junit:4.13-beta-3" level="project" />
     <orderEntry type="library" scope="TEST" name="Maven: org.hamcrest:hamcrest-core:1.3" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/src/main/java/cn/byhieg/arithmetic/SlidingWindow.java b/src/main/java/cn/byhieg/arithmetic/SlidingWindow.java
new file mode 100644
index 0000000..d97e9a9
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/SlidingWindow.java
@@ -0,0 +1,139 @@
+package cn.byhieg.arithmetic;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Created by weizhaoquan on 2019/03/20.
+ */
+
+public class SlidingWindow {
+
+    private AtomicInteger[] timeSlices;
+    /* 队列的总长度  */
+    private final int timeSliceSize;
+    /* 每个时间片的时长 */
+    private final long timeMillisPerSlice;
+    /* 窗口长度 */
+    private final int windowSize;
+
+    /* 当前所使用的时间片位置 */
+    private AtomicInteger cursor = new AtomicInteger(0);
+
+    public static enum Time {
+        MILLISECONDS(1),
+        SECONDS(1000),
+        MINUTES(SECONDS.getMillis() * 60),
+        HOURS(MINUTES.getMillis() * 60),
+        DAYS(HOURS.getMillis() * 24),
+        WEEKS(DAYS.getMillis() * 7);
+
+        private long millis;
+
+        Time(long millis) {
+            this.millis = millis;
+        }
+
+        public long getMillis() {
+            return millis;
+        }
+    }
+
+    public SlidingWindow(int windowSize, Time timeSlice) {
+        this.timeMillisPerSlice = timeSlice.millis;
+        this.windowSize = windowSize;
+        // 保证存储在至少两个window
+        this.timeSliceSize = windowSize * 2 + 1;
+
+        init();
+    }
+
+    /**
+     * 初始化
+     */
+    private void init() {
+        AtomicInteger[] localTimeSlices = new AtomicInteger[timeSliceSize];
+        for (int i = 0; i < timeSliceSize; i++) {
+            localTimeSlices[i] = new AtomicInteger(0);
+        }
+        timeSlices = localTimeSlices;
+    }
+
+    private int locationIndex() {
+        long time = System.currentTimeMillis();
+        return (int) ((time / timeMillisPerSlice) % timeSliceSize);
+    }
+
+    /**
+     * <p>对时间片计数+1，并返回窗口中所有的计数总和
+     * <p>该方法只要调用就一定会对某个时间片进行+1
+     * @return
+     */
+    public int incrementAndSum() {
+        int index = locationIndex();
+        int sum = 0;
+        // cursor等于index，返回true
+        // cursor不等于index，返回false，并会将cursor设置为index
+        int oldCursor = cursor.getAndSet(index);
+        if (oldCursor == index) {
+            // 在当前时间片里继续+1
+            sum += timeSlices[index].incrementAndGet();
+        } else {
+            //轮到新的时间片，置0，可能有其它线程也置了该值，容许
+            timeSlices[index].set(0);
+            // 清零，访问量不大时会有时间片跳跃的情况
+            clearBetween(oldCursor, index);
+
+            sum += timeSlices[index].incrementAndGet();
+        }
+
+        for (int i = 1; i < windowSize; i++) {
+            sum += timeSlices[(index - i + timeSliceSize) % timeSliceSize].get();
+        }
+        return sum;
+    }
+
+    /**
+     * 判断是否允许进行访问，未超过阈值的话才会对某个时间片+1
+     * @param threshold
+     * @return
+     */
+    public boolean allow(int threshold) {
+        int index = locationIndex();
+        int sum = 0;
+        int oldCursor = cursor.getAndSet(index);
+        if (oldCursor != index) {
+            timeSlices[index].set(0);
+            clearBetween(oldCursor, index);
+        }
+        for (int i = 0; i < windowSize; i++) {
+            sum += timeSlices[(index - i + timeSliceSize) % timeSliceSize].get();
+        }
+
+        // 阈值判断
+        if (sum < threshold) {
+            // 未超过阈值才+1
+            timeSlices[index].incrementAndGet();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * <p>将fromIndex~toIndex之间的时间片计数都清零
+     * <p>极端情况下，当循环队列已经走了超过1个timeSliceSize以上，这里的清零并不能如期望的进行
+     * @param fromIndex 不包含
+     * @param toIndex 不包含
+     */
+    private void clearBetween(int fromIndex, int toIndex) {
+        for (int index = (fromIndex + 1) % timeSliceSize; index != toIndex; index = (index + 1) % timeSliceSize) {
+            timeSlices[index].set(0);
+        }
+    }
+
+    public static void main(String[] args) {
+        SlidingWindow window = new SlidingWindow(5, Time.MILLISECONDS);
+        for (int i = 0; i < 10; i++) {
+            System.out.println(window.allow(7));
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/cn/byhieg/arithmetic/TwoDimensionalArray.java b/src/main/java/cn/byhieg/arithmetic/TwoDimensionalArray.java
new file mode 100644
index 0000000..27534ee
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/TwoDimensionalArray.java
@@ -0,0 +1,32 @@
+package cn.byhieg.arithmetic;
+
+/**
+ * Created by weizhaoquan on 2019/04/08.
+ */
+public class TwoDimensionalArray {
+    public static int[][] rotate(int[][] matrix){
+        int n= matrix.length;
+        int[][] m = new int[n][n];
+        for (int row = 0;row < n; row ++) {
+            for (int col=0;col<n;col++) {
+                m[row][col] = matrix[n-1-col][row];
+            }
+        }
+        return m;
+    }
+
+    public static void main(String[] args) {
+        int[][] arry = new int[][] {{1,2,3},{4,5,6},{7,8,9}};
+        int[][] rotate = rotate( arry );
+        printArray(rotate);
+    }
+
+    public static void printArray(int array[][]){
+        for(int i=0;i<array.length; i++) {
+            for(int j = 0; j< array[i].length; j++) {
+                System.out.print(array[i][j]+"、");
+            }
+            System.out.println();
+        }
+    }
+}
diff --git a/src/main/java/cn/byhieg/arithmetic/TwoSum.java b/src/main/java/cn/byhieg/arithmetic/TwoSum.java
new file mode 100644
index 0000000..b3dd37c
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/TwoSum.java
@@ -0,0 +1,41 @@
+package cn.byhieg.arithmetic;
+
+import java.util.Arrays;
+import java.util.HashMap;
+
+/**
+ * Created by weizhaoquan on 2019/05/09.
+ */
+public class TwoSum {
+    public static int[] twoSum1(int[] nums, int target) {
+        HashMap<Integer, Integer> map = new HashMap<>();
+        for(int i = 0; i < nums.length; i++) {
+            map.put(nums[i], i);
+        }
+        for(int i = 0; i < nums.length; i++){
+            int val = target - nums[i];
+            if(map.containsKey(val) && map.get(val) != i){
+                return new int[]{i, map.get(val)};
+            }
+        }
+        throw new RuntimeException("No such solution!");
+    }
+    public static int[] twoSum2(int[] nums, int target) {
+        HashMap<Integer, Integer> map = new HashMap<>();
+        for(int i = 0; i < nums.length; i++){
+            int val = target - nums[i];
+            if(map.containsKey(val)) {// 肯定不会map.get(val) == i
+                return new int[]{i, map.get(val)};
+            }
+            map.put(nums[i], i);
+        }
+        throw new RuntimeException("No such solution!");
+    }
+
+    public static void main(String[] args) {
+        int[] nums = {2,7,11,15};
+        int taget = 9;
+        int[] ints = twoSum2( nums, taget );
+        System.out.printf( Arrays.toString(ints) );
+    }
+}
diff --git a/src/main/java/cn/byhieg/arithmetic/sort/BubbleSort.java b/src/main/java/cn/byhieg/arithmetic/sort/BubbleSort.java
new file mode 100644
index 0000000..a68c190
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/sort/BubbleSort.java
@@ -0,0 +1,78 @@
+package cn.byhieg.arithmetic.sort;
+
+/**
+ * Created by weizhaoquan on 2019/04/17.
+ */
+public class BubbleSort {
+
+    static void swap (int[] arr,int i,int j){
+        int temp = arr[i];
+        arr[i]=arr[j];
+        arr[j]=temp;
+    }
+    static void bubbleSort1(int[] arr){
+        for (int end = arr.length-1;end>0;end--) {
+            boolean isSort = true;
+            for (int i = 0 ;i<end;i++) {
+                if (arr[i]>arr[i+1]) {
+                    swap( arr,i,i+1 );
+                    isSort = false;
+                }
+            }
+            if (isSort) {
+                break;
+            }
+        }
+    }
+
+    static void bubbleSort2(int[] arr){
+        for (int end = arr.length;end >0 ;end--) {
+            int border = 0 ;
+            for (int i= 0;i<end;i++) {
+                swap(arr,i,i+1);
+                border = i + 1;
+            }
+            end = border;
+        }
+    }
+
+    public static int[] bubbleSort(int[] array){
+        if (array.length == 0) {
+            return array;
+        }
+        for (int i = 0;i<array.length-1;i++) {
+            for (int j=0;j<array.length -1-i;j++ ) {
+                if (array[j+1]<array[j]) {
+                    int temp = array[j+1];
+                    array[j+1] = array[j];
+                    array[j] = temp;
+                }
+            }
+        }
+
+        return array;
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {6,3,5,7,3,7,8,9,1};
+        int[] ints = bubbleSort( arr );
+        System.out.printf( "1排序后的数组为：" );
+        for (int num :ints) {
+            System.out.printf( num+" " );
+        }
+        System.out.println(  );
+        int[] arr1 = {6,3,5,7,3,7,8,9,1};
+        bubbleSort1( arr1 );
+        System.out.printf( "2排序后的数组为：" );
+        for (int num :arr1) {
+            System.out.printf( num+" " );
+        }
+        System.out.println(  );
+        int[] arr2 = {6,3,5,7,3,7,8,9,1};
+        bubbleSort1( arr2 );
+        System.out.printf( "2排序后的数组为：" );
+        for (int num :arr2) {
+            System.out.printf( num+" " );
+        }
+    }
+}
diff --git a/src/main/java/cn/byhieg/arithmetic/sort/InsertSort.java b/src/main/java/cn/byhieg/arithmetic/sort/InsertSort.java
new file mode 100644
index 0000000..725e904
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/sort/InsertSort.java
@@ -0,0 +1,35 @@
+package cn.byhieg.arithmetic.sort;
+
+import java.util.Arrays;
+
+/**
+ * Created by weizhaoquan on 2019/05/29.
+ */
+public class InsertSort {
+    static int[] insertSort(int[] sourceArr){
+        int[] arr = Arrays.copyOf(sourceArr,sourceArr.length);
+        for (int i = 1;i<arr.length;i++) {
+            int  temp = arr[i];
+            int j = i;
+            while (j>0 && temp<arr[j-1]) {
+                arr[j]=arr[j-1];
+                j--;
+            }
+            if (j!=i) {
+                arr[j] = temp;
+            }
+
+        }
+        return arr;
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {6,3,5,7,3,7,8,9,1};
+        int[] arrs = insertSort( arr );
+        System.out.printf( "1排序后的数组为 ：" );
+        for (int num :arrs) {
+            System.out.printf( num + " " );
+        }
+
+    }
+}
diff --git a/src/main/java/cn/byhieg/arithmetic/sort/SelectSort.java b/src/main/java/cn/byhieg/arithmetic/sort/SelectSort.java
new file mode 100644
index 0000000..d76b01e
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/sort/SelectSort.java
@@ -0,0 +1,55 @@
+package cn.byhieg.arithmetic.sort;
+
+import java.util.Arrays;
+
+public class SelectSort {
+    static void swap(int[] arr,int i,int j){
+        int temp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = temp;
+    }
+
+    static void selectSort(int[] arr){
+        for (int i = 0;i<arr.length;i++) {
+            int minIndex =  i;
+            for (int j=i+1;j<arr.length;j++) {
+                minIndex = arr[j]<arr[minIndex] ? j : minIndex;
+                swap(arr,i,minIndex);
+            }
+        }
+    }
+
+    static int[] selectSort1(int[] sourceArr){
+        int[] arr = Arrays.copyOf(sourceArr,sourceArr.length);
+        for (int i = 0;i<arr.length-1;i++) {
+            int min = i;
+            for(int j=i+1;j<arr.length;j++){
+                if (arr[j]<arr[min]) {
+                    min = j;
+                }
+            }
+            if (i!=min) {
+                int temp = arr[i];
+                arr[i]=arr[min];
+                arr[min]=temp;
+            }
+        }
+        return arr;
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {6,3,5,7,3,7,8,9,1};
+        selectSort( arr );
+        System.out.printf( "1排序后的数组为 ：" );
+        for (int num :arr) {
+            System.out.printf( num + " " );
+        }
+        System.out.println(  );
+        int[] arr1 = {6,3,5,7,3,7,8,9,1};
+        int[] arr11 = selectSort1(arr1);
+        System.out.printf( "2排序后的数组为 ：" );
+        for (int num :arr11) {
+            System.out.printf( num+" " );
+        }
+    }
+}
diff --git a/src/main/java/cn/byhieg/arithmetic/sort/ShellSort.java b/src/main/java/cn/byhieg/arithmetic/sort/ShellSort.java
new file mode 100644
index 0000000..a9ebb41
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/sort/ShellSort.java
@@ -0,0 +1,28 @@
+package cn.byhieg.arithmetic.sort;
+
+/**
+ * Created by weizhaoquan on 2019/06/04.
+ */
+public class ShellSort {
+    static void shellSort(int[] arr){
+        for (int g=  arr.length;g>0;g/=2) {
+            for (int end = g;end<arr.length;end++) {
+                int key = arr[end],i;
+                for (i= end-g;i>=0 && key <arr[i];i-=g) {
+                    arr[i+g]= arr[i];
+                }
+                arr[i+g]= key;
+            }
+        }
+
+    }
+    public static void main(String[] args) {
+        int[] arr = {6,3,5,7,3,7,8,9,1};
+        shellSort( arr );
+        System.out.printf( "1排序后的数组为 ：" );
+        for (int num :arr) {
+            System.out.printf( num + " " );
+        }
+        System.out.println(  );
+    }
+}
diff --git a/src/main/java/cn/byhieg/arithmetic/sort/dichotomyInsertSort.java b/src/main/java/cn/byhieg/arithmetic/sort/dichotomyInsertSort.java
new file mode 100644
index 0000000..35d4f05
--- /dev/null
+++ b/src/main/java/cn/byhieg/arithmetic/sort/dichotomyInsertSort.java
@@ -0,0 +1,36 @@
+package cn.byhieg.arithmetic.sort;
+
+/**
+ * Created by weizhaoquan on 2019/05/29.
+ * 二分查找型
+ */
+public class dichotomyInsertSort {
+    static void insertSort(int[] arr){
+        for (int i = 1;i<arr.length;i++ ) {
+            int key = arr[i];
+            int L= 0,R=i-1;
+            while(L<=R){
+                int mid= L+(R-L)/2;
+                if (arr[mid]>key) {
+                    R= mid-1;
+                }else{
+                    L=mid+1;
+                }
+            }
+            for (int j = i-1;j>=L;j--) {
+                arr[j+1] =arr[j];
+            }
+            arr[L] = key;
+
+        }
+    }
+    public static void main(String[] args){
+        int[] arr = {3,6,5,7,3,7,8,9,1};
+        insertSort(arr);
+        System.out.printf( "1排序后的数组为 ：" );
+        for (int num:arr) {
+            System.out.printf(" "+num);
+        }
+
+    }
+}