diff --git a/.idea/$PRODUCT_WORKSPACE_FILE$ b/.idea/$PRODUCT_WORKSPACE_FILE$
new file mode 100644
index 0000000000000000000000000000000000000000..739758834431274bbb950b8315c107d007da3849
--- /dev/null
+++ b/.idea/$PRODUCT_WORKSPACE_FILE$
@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="masterDetails">
+    <states>
+      <state key="GlobalLibrariesConfigurable.UI">
+        <settings>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="JdkListConfigurable.UI">
+        <settings>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="ProjectJDKs.UI">
+        <settings>
+          <last-edited>1.8</last-edited>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+      <state key="ProjectLibrariesConfigurable.UI">
+        <settings>
+          <splitter-proportions>
+            <option name="proportions">
+              <list>
+                <option value="0.2" />
+              </list>
+            </option>
+          </splitter-proportions>
+        </settings>
+      </state>
+    </states>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..5c98b428844d9f7d529e2b6fb918d15bf072f3df
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,2 @@
+# Default ignored files
+/workspace.xml
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000000000000000000000000000000000000..639900d13c6182e452e33a3bd638e70a0146c785
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 0000000000000000000000000000000000000000..375e35c14bbe6b32bb1a2d81eb77c40cbc1d2383
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/lec08-sort.iml" filepath="$PROJECT_DIR$/lec08-sort.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000000000000000000000000000000000000..94a25f7f4cb416c083d265558da75d457237d671
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/lec08-sort.iml b/lec08-sort.iml
new file mode 100644
index 0000000000000000000000000000000000000000..8021953ed9f8cc6cd6d71c79462bad4cd2b5394c
--- /dev/null
+++ b/lec08-sort.iml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file
diff --git a/work/BubbleSort/BubbleSort.class b/work/BubbleSort/BubbleSort.class
new file mode 100644
index 0000000000000000000000000000000000000000..9ce42c9266d6625452361139d2a77d1a702a631a
Binary files /dev/null and b/work/BubbleSort/BubbleSort.class differ
diff --git a/work/BubbleSort/BubbleSort.java b/work/BubbleSort/BubbleSort.java
new file mode 100644
index 0000000000000000000000000000000000000000..6aed21c752a5893ee322b33c5736e4faad427e40
--- /dev/null
+++ b/work/BubbleSort/BubbleSort.java
@@ -0,0 +1,19 @@
+import java.util.*;
+public class BubbleSort {
+    public static void main(String[] args) {
+        int[] arr = {12,56,3,78,39};//,1,2,5,4,6,7,8,33,22,44,55,66,77
+		long n1 = System.nanoTime();
+        for (int i = 0; i < arr.length; i++) {
+            for (int j = 0; j < arr.length - 1 - i; j++) {//每次循环结束，大的到最后放
+                if (arr[j] > arr[j + 1]) {
+                    int temp = arr[j];
+                    arr[j] = arr[j + 1];
+                    arr[j + 1] = temp;
+                }
+            }
+        }
+        System.out.println(Arrays.toString(arr));
+		long n2 = System.nanoTime();
+		System.out.printf("\n冒泡排序用时："+(n2-n1)/1000000+"毫秒\n");
+    }
+}
\ No newline at end of file
diff --git a/work/InsertSort/InsertSort.class b/work/InsertSort/InsertSort.class
new file mode 100644
index 0000000000000000000000000000000000000000..9f704a3238c63bbd749203d21e5034e06ec21e2b
Binary files /dev/null and b/work/InsertSort/InsertSort.class differ
diff --git a/work/InsertSort/InsertSort.java b/work/InsertSort/InsertSort.java
new file mode 100644
index 0000000000000000000000000000000000000000..12441f299f959dc53044a1c31bc7772134b3c00f
--- /dev/null
+++ b/work/InsertSort/InsertSort.java
@@ -0,0 +1,27 @@
+import java.util.*;
+public class InsertSort{
+	public static void main(String[] args) {
+     int[] array={12,56,3,78,39};
+	 double n1 = System.nanoTime();
+	 test(array);
+	 double n2 = System.nanoTime();
+	 System.out.printf("\n插入排序用时："+(n2-n1)/1000000+"毫秒\n");
+	}
+
+	public static void test(int[] array) {
+		int i,j,temp;
+		for(i=1;i<array.length;i++) {//i 1~4
+			temp=array[i];
+			for(j=i-1;j>=0;--j) {//注意这里--j，有机会让j到-1
+				if(temp>array[j]) {
+					break;
+				}else {
+					array[j+1]=array[j];
+				}
+			}
+			array[j+1]=temp;
+		}
+		System.out.println(Arrays.toString(array));
+	}
+}
+
diff --git a/work/MergeSort/Main.class b/work/MergeSort/Main.class
new file mode 100644
index 0000000000000000000000000000000000000000..2cefec554cf196ebb2ca17909cc12af70f1df685
Binary files /dev/null and b/work/MergeSort/Main.class differ
diff --git a/work/MergeSort/Main.java b/work/MergeSort/Main.java
new file mode 100644
index 0000000000000000000000000000000000000000..1e5c270ddb6c3b53393b3ee7e9eaab57f8c8d9c2
--- /dev/null
+++ b/work/MergeSort/Main.java
@@ -0,0 +1,49 @@
+import java.util.Arrays;
+public class Main{
+    public static void main(String[] args){
+        int[] arr = {12,56,3,78,39};
+		double n1 = System.nanoTime();
+        sort(arr,0,arr.length-1);
+        System.out.println(Arrays.toString(arr));
+		double n2 = System.nanoTime();
+		System.out.printf("\n归并排序用时："+(n2-n1)/1000000+"毫秒\n");
+    }
+
+	public static int[] sort(int[] a,int low,int high){
+        int mid = (low+high)/2;
+        if(low<high){
+            sort(a,low,mid);
+            sort(a,mid+1,high);
+            //左右归并
+            merge(a,low,mid,high);
+        }
+        return a;
+    }
+
+	public static void merge(int[] a, int low, int mid, int high) {
+        int[] temp = new int[high-low+1];
+        int i= low;
+        int j = mid+1;
+        int k=0;
+        // 把较小的数先移到新数组中
+        while(i<=mid && j<=high){
+            if(a[i]<a[j]){
+                temp[k++] = a[i++];
+            }else{
+                temp[k++] = a[j++];
+            }
+        }
+        // 把左边剩余的数移入数组 
+        while(i<=mid){
+            temp[k++] = a[i++];
+        }
+        // 把右边边剩余的数移入数组
+        while(j<=high){
+            temp[k++] = a[j++];
+        }
+        // 把新数组中的数覆盖nums数组
+        for(int x=0;x<temp.length;x++){
+            a[x+low] = temp[x];
+        }
+    }
+}
\ No newline at end of file
diff --git a/work/QuickSort/QuickSort.class b/work/QuickSort/QuickSort.class
new file mode 100644
index 0000000000000000000000000000000000000000..efa9c85d56f718eb8b26263a97bac61770b4b66e
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diff --git a/work/QuickSort/QuickSort.java b/work/QuickSort/QuickSort.java
new file mode 100644
index 0000000000000000000000000000000000000000..7714724145be342e34e28e247dff4507d81625ba
--- /dev/null
+++ b/work/QuickSort/QuickSort.java
@@ -0,0 +1,48 @@
+import java.util.Arrays;
+ 
+public class QuickSort{
+    public static void main(String[] args){
+        Integer[] arr = {12,56,3,78,39};
+		double n1 = System.nanoTime();
+        quickSort(arr,0,arr.length-1);
+        System.out.println(Arrays.toString(arr));
+		double n2 = System.nanoTime();
+		System.out.printf("\n快速排序用时："+(n2-n1)/1000000+"毫秒\n");
+    }
+ 
+    //排序方法-假设从小到大排序
+    public static void quickSort(Integer[] arr,int low,int high){//l=0 h=9
+        if(low < high){
+            int part=partition(arr,low,high);
+            //递归调用
+            quickSort(arr,low,part-1);
+            quickSort(arr,part+1,high);
+        }
+    }
+ 
+    //划分方法
+    private static int partition(Integer[] arr,int low,int high){
+        //使用 r[low]作为枢轴元素
+        int pivot = arr[low];
+        //从两端交替向内扫描
+        while(low < high){
+            while(low<high && arr[high] >= pivot) {
+				high--;
+			}
+            //将比 pivot 小的元素移向低端
+            arr[low] = arr[high];
+            while(low<high && arr[low] <= pivot){
+				low++;
+			}
+            //将比 pivot 大的元素移向高端
+            arr[high] = arr[low];
+        }
+        //设置枢轴
+        arr[low]=pivot;
+		//System.out.println(Arrays.toString(arr));
+
+        //返回枢轴元素位置
+        return low;
+    }
+ 
+}
\ No newline at end of file
diff --git a/work/SelectSort/SelectSort.class b/work/SelectSort/SelectSort.class
new file mode 100644
index 0000000000000000000000000000000000000000..a55d0575c12ae4c664cb8c5808ee359f6f09ed70
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diff --git a/work/SelectSort/SelectSort.java b/work/SelectSort/SelectSort.java
new file mode 100644
index 0000000000000000000000000000000000000000..722fa6f051f5c6cecd395ac80d958fbcf629eae9
--- /dev/null
+++ b/work/SelectSort/SelectSort.java
@@ -0,0 +1,32 @@
+import java.util.Arrays;
+public class SelectSort {
+	public static void main(String[] args) {
+		//模拟数据
+		int[] array = {12,56,3,78,39};
+		long n1 = System.nanoTime();
+		selectSort(array);
+		System.out.println(Arrays.toString(array));
+		long n2 = System.nanoTime();
+		System.out.printf("\n选择排序用时："+(n2-n1)/1000000+"毫秒\n");
+	}
+	//12,56,3,78,39
+	public static void selectSort(int[] arr){
+		for(int i = 0; i < arr.length-1; i++){//每次循环结束把最小的放在前面
+			int min = i;
+			for(int j = i+1; j <arr.length ;j++){
+				if(arr[j]<arr[min]){
+					min = j;
+				}
+			}
+			if(min!=i){
+				swap(arr, i, min);
+			}
+		}
+	}
+	//完成数组两元素间交换
+	public static void swap(int[] arr,int a,int b){
+		int temp = arr[a];
+		arr[a] = arr[b];
+		arr[b] = temp;
+	}
+}
\ No newline at end of file
diff --git a/work/ShellSort/ShellSort.class b/work/ShellSort/ShellSort.class
new file mode 100644
index 0000000000000000000000000000000000000000..bda7e07a33f7e29c6aa38a300b8d1a04b093df70
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diff --git a/work/ShellSort/ShellSort.java b/work/ShellSort/ShellSort.java
new file mode 100644
index 0000000000000000000000000000000000000000..f002c122226e0e5b9d821842ebe4862f28677932
--- /dev/null
+++ b/work/ShellSort/ShellSort.java
@@ -0,0 +1,30 @@
+import java.util.Arrays;
+public class ShellSort {
+    public static void main(String[] args) {
+        int[] arr = {12,56,3,78,39};
+		double n1 = System.nanoTime();
+        shellSort(arr);
+		System.out.println(Arrays.toString(arr));
+		double n2 = System.nanoTime();
+		System.out.printf("\n希尔排序用时："+(n2-n1)/1000000+"毫秒\n");
+    }
+
+    public static void shellSort(int[] arr) {
+        //step:步长
+        for (int step = arr.length / 2; step > 0; step /= 2) {
+            //对一个步长区间进行比较 [step,arr.length)
+            for (int i = step; i < arr.length; i++) {
+                int value = arr[i];
+                int j;
+
+                //对步长区间中具体的元素进行比较
+                for (j = i - step; j >= 0 && arr[j] > value; j -= step) {
+                    //j为左区间的取值，j+step为右区间与左区间的对应值。
+                    arr[j + step] = arr[j]; 
+                }
+                //此时step为一个负数，[j + step]为左区间上的初始交换值
+                arr[j + step] = value;  
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git "a/work/\347\256\227\346\263\225\347\224\250\346\227\266/1.png" "b/work/\347\256\227\346\263\225\347\224\250\346\227\266/1.png"
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