diff --git a/code_min_integer_2018.cpp b/code_min_integer_2018.cpp
index 09e60ca..1b4855c 100644
--- a/code_min_integer_2018.cpp
+++ b/code_min_integer_2018.cpp
@@ -3,15 +3,15 @@
 #include<string.h>
 
 void min_integer(int a[], int n) {
-    int* tmp = (int*)malloc(4 * n);
-    memset(tmp, 0, n * 4);
+    int* tmp = (int*)malloc(4 * n);//动态分配数组空间
+    memset(tmp, 0, n * 4);//空间置0
     int i;
     for (i = 0;i < n;i++) {
         if (a[i] <= n && a[i] > 0) {
-            tmp[a[i] - 1] = 1;
+            tmp[a[i] - 1] = 1;//将对应map位的元素置为1
         }
     }
-    for (i = 0;i < n;i++) {
+    for (i = 0;i < n;i++) {//遍历得到第一个缺失的正整数
         if (tmp[i] == 0)break;
     }
     printf("%d", i + 1);
diff --git a/code_quicksort_2016.cpp b/code_quicksort_2016.cpp
index e66c42b..4232f52 100644
--- a/code_quicksort_2016.cpp
+++ b/code_quicksort_2016.cpp
@@ -9,6 +9,7 @@ void printArr(int a[], int n) {
 }
 
 int Partition(int A[], int low, int high) {
+	//��������
 	int pivot = A[low]; //ѡȡ��һ����Ϊ����
 	while (low < high) {
 		while (low < high && A[high] >= pivot)
@@ -24,7 +25,7 @@ int Partition(int A[], int low, int high) {
 void QuickDivideSort(int A[], int low, int high, int n) {
 	if (low < high) {
 		int pivot = Partition(A, low, high);
-		if (pivot < n / 2)
+		if (pivot < n / 2)//���ֳ�n/2��λ��
 			QuickDivideSort(A, pivot + 1, high, n);
 		else
 			QuickDivideSort(A, low, pivot - 1, n);
diff --git a/code_tree_2017.cpp b/code_tree_2017.cpp
index 6e1be91..0c7d213 100644
--- a/code_tree_2017.cpp
+++ b/code_tree_2017.cpp
@@ -1,5 +1,6 @@
 #include<stdio.h>
 #include <stdlib.h>
+
 typedef struct node {
     char data[10];
     struct node* left, * right;
@@ -11,15 +12,16 @@ void midQuation(BTree* T) {
         bool flag = false;
         flag = (t == '+' || t == '-' || t == '*' || t == '/');
         if (flag)printf("(");
-        if (T->left != NULL)midQuation(T->left);
-        for (int i = 0;T->data[i] != '\0';i++) {
-            printf("%c", T->data[i]);
-        }
-        if (T->right != NULL)midQuation(T->right);
+        if (T->left != NULL)midQuation(T->left);//左子树递归
+        printf("%c", T->data[0]);//打印当前节点
+        if (T->right != NULL)midQuation(T->right);//右子树递归
         if (flag)printf(")");
     }
 }
 
+/**
+ * 创建二叉树
+ */
 void createTree(BTree* node, char c[], int pos, int length) {
     if (pos < length) {//填入数据
         node->data[0] = c[pos];