diff --git a/README.md b/README.md
index ad31902..656b18c 100644
--- a/README.md
+++ b/README.md
@@ -248,9 +248,6 @@ $$
   - [表达式求值](ch3/stack-applications/README.md#2-表达式求值)
   - [递归](ch3/stack-applications/README.md#3-递归)
 - [队列的应用](ch3/README.md#5-队列的应用)
-  - 树的层次遍历
-  - 图的广度优先遍历
-  - 操作系统资源分配
 - [矩阵的压缩存储](ch3/matrix/README.md#矩阵的压缩存储)
   - [对称矩阵](ch3/matrix/README.md#3-对称矩阵)
   - [三角矩阵](ch3/matrix/README.md#4-三角矩阵)
@@ -292,3 +289,29 @@ $$
   - [树和森林的遍历](ch5/tree-traversal/README.md#树与森林)
   - [树和森林及二叉树的转换](ch5/tree-traversal/README.md#树与森林)
   - [树的应用：查并集](ch5/tree-applications/README.md#1-并查集)
+
+## 7. [图](ch6/README.md#图)
+
+- [逻辑结构](ch6/README.md#图)
+  - [图的定义](ch6/README.md#图)
+  - [相关概念](ch6/concept/README.md#图的基本概念)
+    - [无向图 & 有向图](ch6/concept/README.md#1-无向图-&-有向图)
+    - [完全图](ch6/concept/README.md#3-完全图)
+    - [子图](ch6/concept/README.md#4-子图)
+    - [连通分量 & 强连通分量](ch6/concept/README.md#7-连通分量-&-强连通分量)
+    - [带权图(网)](ch6/concept/README.md#11-网)
+- [存储结构](ch6/storage/README.md#图的存储结构)
+  - [邻接矩阵](ch6/storage/README.md#1-邻接矩阵法)
+  - [邻接表](ch6/storage/README.md#2-邻接表法)
+  - [十字链表](ch6/storage/README.md#3-十字链表)
+  - [邻接多重表](ch6/storage/README.md#4-邻接多重表)
+- [基本操作](ch6/operation/README.md#图的基本操作)
+- [图的遍历](ch6/traversal/README.md#图的遍历)
+  - [广度优先搜索](ch6/traversal/README.md#1-广度优先搜索)
+  - [深度优先搜索](ch6/traversal/README.md#2-深度优先搜索)
+  - [遍历与连通性](ch6/traversal/README.md#3-遍历与连通性问题)
+- [图的应用](ch6/applications/README.md#图的应用)
+  - [最小生成树](ch6/applications/README.md#1-最小生成树)
+  - [最短路径](ch6/applications/README.md#2-最短路径)
+  - [拓扑排序](ch6/applications/README.md#3-拓扑排序)
+  - [关键路径](ch6/applications/README.md#4-关键路径)
diff --git a/ch5/tree-applications/README.md b/ch5/tree-applications/README.md
index 9b3eb30..f827279 100644
--- a/ch5/tree-applications/README.md
+++ b/ch5/tree-applications/README.md
@@ -4,7 +4,7 @@
 
 一种简单的集合表示。
 
-通常用书的双亲表示法作为并查集的存储结构。
+通常用树的双亲表示法作为并查集的存储结构。
 
 通常用数组元素的下标代表元素名，用根结点的下标代表子集合名，根结点的双亲结点为负数。
 
diff --git a/ch6/README.md b/ch6/README.md
new file mode 100644
index 0000000..981b61f
--- /dev/null
+++ b/ch6/README.md
@@ -0,0 +1,78 @@
+# 图
+
+## 1. [基本概念](concept/README.md#图的基本概念)
+
+图 $G$ 是由顶点集 $V$ 和边集 $E$ 组成，记为：
+
+$$
+G=(V,E)
+$$
+
+其中，
+
+- $V(G)$ 表示图 $G$ 中顶点的有限非空集；
+- $E(G)$ 表示图 $G$ 中顶点之间的关系（边）的集合。
+
+$\left \vert V \right \vert$ 表示图 $G$ 中顶点的个数，也称图 $G$ 的阶。
+
+$\left \vert E \right \vert$ 表示图 $G$ 中边的条数。
+
+![图](graph.png)
+
+$$
+V=\{A,B,C,D,E\},\left \vert V \right \vert=5
+$$
+
+$$
+E=\{(A,B),(A,C),(A,E),(B,C),(C,D),(C,E)\},\left \vert E \right \vert=6
+$$
+
+线性表、树都可以为空，但图不能为空。
+
+- [无向图 & 有向图](concept/README.md#1-无向图-&-有向图)
+- [简单图 & 多重图](concept/README.md#2-简单图-&-多重图)
+- [完全图](concept/README.md#3-完全图)
+- [子图](concept/README.md#4-子图)
+- [连通 & 强连通](concept/README.md#5-连通-&-强连通)
+- [连通图 & 强连通图](concept/README.md#6-连通图-&-强连通图)
+- [连通分量 & 强连通分量](concept/README.md#7-连通分量-&-强连通分量)
+- [极小连通子图](concept/README.md#8-极小连通子图)
+- [生成树、生成森林](concept/README.md#9-生成树、生成森林)
+- [顶点的度](concept/README.md#10-顶点的度)
+- [网](concept/README.md#11-网)
+- [稠密图 & 稀疏图](concept/README.md#12-稠密图-&-稀疏图)
+- [有向树](concept/README.md#13-有向树)
+- [路径](concept/README.md#14-路径)
+- [路径长度](concept/README.md#15-路径长度)
+- [回路](concept/README.md#16-回路)
+
+## 2. [存储结构](storage/README.md#图的存储结构)
+
+- [邻接矩阵](storage/README.md#1-邻接矩阵法)
+- [邻接表](storage/README.md#2-邻接表法)
+- [十字链表](storage/README.md#3-十字链表)
+- [邻接多重表](storage/README.md#4-邻接多重表)
+
+## 3. [基本操作](operation/README.md#图的基本操作)
+
+- [边是否存在](operation/README.md#1-边是否存在)
+- [顶点的邻接边](operation/README.md#2-顶点的邻接边)
+- [插入顶点](operation/README.md#3-插入顶点)
+- [删除顶点](operation/README.md#4-删除顶点)
+- [增加边](operation/README.md#5-增加边)
+- [删除边](operation/README.md#6-删除边)
+- [第一条边和下一条边](operation/README.md#7-第一条边和下一条边)
+- [获取权值和设置权值](operation/README.md#8-获取权值和设置权值)
+
+## 4. [遍历](traversal/README.md#图的遍历)
+
+- [广度优先搜索](traversal/README.md#1-广度优先搜索)
+- [深度优先搜索](traversal/README.md#2-深度优先搜索)
+- [遍历与连通性问题](traversal/README.md#3-遍历与连通性问题)
+
+## 5. [应用](applications/README.md#图的应用)
+
+- [最小生成树](applications/README.md#1-最小生成树)
+- [最短路径](applications/README.md#2-最短路径)
+- [拓扑排序](applications/README.md#3-拓扑排序)
+- [关键路径](applications/README.md#4-关键路径)
diff --git a/ch6/applications/README.md b/ch6/applications/README.md
new file mode 100644
index 0000000..04b2c81
--- /dev/null
+++ b/ch6/applications/README.md
@@ -0,0 +1,138 @@
+# 图的应用
+
+## 1. 最小生成树
+
+### 1.1. 概念
+
+![最小生成树1](mst1.png)
+
+![最小生成树2](mst2.png)
+
+![最小生成树3](mst3.png)
+
+### 1.2. 性质
+
+![最小生成树4](mst4.png)
+
+- 所有边的情况皆不相同。
+
+![最小生成树5](mst5.png)
+
+- $n$ 个顶点只有 $n-1$ 条边。
+
+![最小生成树6](mst6.png)
+
+![最小生成树7](mst7.png)
+
+### 1.3. 算法
+
+![最小生成树8](mst8.png)
+
+- 不会产生回路
+- 权值最小
+
+都使用贪心算法策略。
+
+> 考研中多考查算法步骤；代码编写考查较少。
+
+#### 1.3.1. Prim
+
+![最小生成树9](mst9.png)
+
+![最小生成树10](mst10.png)
+
+![最小生成树11](mst11.png)
+
+![最小生成树12](mst12.png)
+
+#### 1.3.2. Kruskal
+
+![最小生成树13](mst13.png)
+
+![最小生成树14](mst14.png)
+
+![最小生成树15](mst15.png)
+
+![最小生成树16](mst16.png)
+
+## 2. 最短路径
+
+![最短路径1](sp1.png)
+
+![最短路径2](sp2.png)
+
+> 考研中多考查算法步骤；代码编写考查较少。
+
+### 2.1. Dijkstra
+
+![最短路径3](sp3.png)
+
+![最短路径4](sp4.png)
+
+![最短路径5](sp5.png)
+
+![最短路径6](sp6.png)
+
+![最短路径7](sp7.png)
+
+![最短路径8](sp8.png)
+
+![最短路径9](sp9.png)
+
+### 2.2. Floyd
+
+![最短路径10](sp10.png)
+
+![最短路径11](sp11.png)
+
+![最短路径12](sp12.png)
+
+## 3. 拓扑排序
+
+### 3.1. 概念
+
+![拓扑排序1](ts1.png)
+
+![拓扑排序2](ts2.png)
+
+### 3.2. 算法思想
+
+![拓扑排序3](ts3.png)
+
+![拓扑排序4](ts4.png)
+
+![拓扑排序5](ts5.png)
+
+![拓扑排序6](ts6.png)
+
+![拓扑排序7](ts7.png)
+
+![拓扑排序8](ts8.png)
+
+## 4. 关键路径
+
+![关键路径1](cp1.png)
+
+- 事件最早发生时间：等待所有前置事件都完成。
+
+![关键路径2](cp2.png)
+
+- 事件最迟发生时间：不延期后置事件的发生。
+
+![关键路径3](cp3.png)
+
+- 活动最早开始时间。
+
+![关键路径4](cp4.png)
+
+- 活动最迟开始时间。
+
+![关键路径5](cp5.png)
+
+- 差额。
+
+![关键路径6](cp6.png)
+
+![关键路径7](cp7.png)
+
+![关键路径8](cp8.png)
diff --git a/ch6/applications/cp1.png b/ch6/applications/cp1.png
new file mode 100644
index 0000000..fbe394f
Binary files /dev/null and b/ch6/applications/cp1.png differ
diff --git a/ch6/applications/cp2.png b/ch6/applications/cp2.png
new file mode 100644
index 0000000..9ca655b
Binary files /dev/null and b/ch6/applications/cp2.png differ
diff --git a/ch6/applications/cp3.png b/ch6/applications/cp3.png
new file mode 100644
index 0000000..a145d14
Binary files /dev/null and b/ch6/applications/cp3.png differ
diff --git a/ch6/applications/cp4.png b/ch6/applications/cp4.png
new file mode 100644
index 0000000..549a946
Binary files /dev/null and b/ch6/applications/cp4.png differ
diff --git a/ch6/applications/cp5.png b/ch6/applications/cp5.png
new file mode 100644
index 0000000..842ddaf
Binary files /dev/null and b/ch6/applications/cp5.png differ
diff --git a/ch6/applications/cp6.png b/ch6/applications/cp6.png
new file mode 100644
index 0000000..015dfaf
Binary files /dev/null and b/ch6/applications/cp6.png differ
diff --git a/ch6/applications/cp7.png b/ch6/applications/cp7.png
new file mode 100644
index 0000000..249e62e
Binary files /dev/null and b/ch6/applications/cp7.png differ
diff --git a/ch6/applications/cp8.png b/ch6/applications/cp8.png
new file mode 100644
index 0000000..1c8aaf0
Binary files /dev/null and b/ch6/applications/cp8.png differ
diff --git a/ch6/applications/mst1.png b/ch6/applications/mst1.png
new file mode 100644
index 0000000..28edb84
Binary files /dev/null and b/ch6/applications/mst1.png differ
diff --git a/ch6/applications/mst10.png b/ch6/applications/mst10.png
new file mode 100644
index 0000000..3862242
Binary files /dev/null and b/ch6/applications/mst10.png differ
diff --git a/ch6/applications/mst11.png b/ch6/applications/mst11.png
new file mode 100644
index 0000000..5b1dbc8
Binary files /dev/null and b/ch6/applications/mst11.png differ
diff --git a/ch6/applications/mst12.png b/ch6/applications/mst12.png
new file mode 100644
index 0000000..3fedd46
Binary files /dev/null and b/ch6/applications/mst12.png differ
diff --git a/ch6/applications/mst13.png b/ch6/applications/mst13.png
new file mode 100644
index 0000000..d92654f
Binary files /dev/null and b/ch6/applications/mst13.png differ
diff --git a/ch6/applications/mst14.png b/ch6/applications/mst14.png
new file mode 100644
index 0000000..1c1457e
Binary files /dev/null and b/ch6/applications/mst14.png differ
diff --git a/ch6/applications/mst15.png b/ch6/applications/mst15.png
new file mode 100644
index 0000000..aaf3d5c
Binary files /dev/null and b/ch6/applications/mst15.png differ
diff --git a/ch6/applications/mst16.png b/ch6/applications/mst16.png
new file mode 100644
index 0000000..85f3a21
Binary files /dev/null and b/ch6/applications/mst16.png differ
diff --git a/ch6/applications/mst2.png b/ch6/applications/mst2.png
new file mode 100644
index 0000000..af579a9
Binary files /dev/null and b/ch6/applications/mst2.png differ
diff --git a/ch6/applications/mst3.png b/ch6/applications/mst3.png
new file mode 100644
index 0000000..16d9b19
Binary files /dev/null and b/ch6/applications/mst3.png differ
diff --git a/ch6/applications/mst4.png b/ch6/applications/mst4.png
new file mode 100644
index 0000000..59fbf58
Binary files /dev/null and b/ch6/applications/mst4.png differ
diff --git a/ch6/applications/mst5.png b/ch6/applications/mst5.png
new file mode 100644
index 0000000..b601cbc
Binary files /dev/null and b/ch6/applications/mst5.png differ
diff --git a/ch6/applications/mst6.png b/ch6/applications/mst6.png
new file mode 100644
index 0000000..b981fc4
Binary files /dev/null and b/ch6/applications/mst6.png differ
diff --git a/ch6/applications/mst7.png b/ch6/applications/mst7.png
new file mode 100644
index 0000000..537f06b
Binary files /dev/null and b/ch6/applications/mst7.png differ
diff --git a/ch6/applications/mst8.png b/ch6/applications/mst8.png
new file mode 100644
index 0000000..2bb9af4
Binary files /dev/null and b/ch6/applications/mst8.png differ
diff --git a/ch6/applications/mst9.png b/ch6/applications/mst9.png
new file mode 100644
index 0000000..5582956
Binary files /dev/null and b/ch6/applications/mst9.png differ
diff --git a/ch6/applications/sp1.png b/ch6/applications/sp1.png
new file mode 100644
index 0000000..0a80bf5
Binary files /dev/null and b/ch6/applications/sp1.png differ
diff --git a/ch6/applications/sp10.png b/ch6/applications/sp10.png
new file mode 100644
index 0000000..5ff5011
Binary files /dev/null and b/ch6/applications/sp10.png differ
diff --git a/ch6/applications/sp11.png b/ch6/applications/sp11.png
new file mode 100644
index 0000000..9279380
Binary files /dev/null and b/ch6/applications/sp11.png differ
diff --git a/ch6/applications/sp12.png b/ch6/applications/sp12.png
new file mode 100644
index 0000000..dbdb19a
Binary files /dev/null and b/ch6/applications/sp12.png differ
diff --git a/ch6/applications/sp2.png b/ch6/applications/sp2.png
new file mode 100644
index 0000000..127f4b6
Binary files /dev/null and b/ch6/applications/sp2.png differ
diff --git a/ch6/applications/sp3.png b/ch6/applications/sp3.png
new file mode 100644
index 0000000..2f2c019
Binary files /dev/null and b/ch6/applications/sp3.png differ
diff --git a/ch6/applications/sp4.png b/ch6/applications/sp4.png
new file mode 100644
index 0000000..76716a5
Binary files /dev/null and b/ch6/applications/sp4.png differ
diff --git a/ch6/applications/sp5.png b/ch6/applications/sp5.png
new file mode 100644
index 0000000..b5904a1
Binary files /dev/null and b/ch6/applications/sp5.png differ
diff --git a/ch6/applications/sp6.png b/ch6/applications/sp6.png
new file mode 100644
index 0000000..ea508ec
Binary files /dev/null and b/ch6/applications/sp6.png differ
diff --git a/ch6/applications/sp7.png b/ch6/applications/sp7.png
new file mode 100644
index 0000000..f6a642f
Binary files /dev/null and b/ch6/applications/sp7.png differ
diff --git a/ch6/applications/sp8.png b/ch6/applications/sp8.png
new file mode 100644
index 0000000..d1f1737
Binary files /dev/null and b/ch6/applications/sp8.png differ
diff --git a/ch6/applications/sp9.png b/ch6/applications/sp9.png
new file mode 100644
index 0000000..08dd021
Binary files /dev/null and b/ch6/applications/sp9.png differ
diff --git a/ch6/applications/ts1.png b/ch6/applications/ts1.png
new file mode 100644
index 0000000..9be10da
Binary files /dev/null and b/ch6/applications/ts1.png differ
diff --git a/ch6/applications/ts2.png b/ch6/applications/ts2.png
new file mode 100644
index 0000000..7190b8d
Binary files /dev/null and b/ch6/applications/ts2.png differ
diff --git a/ch6/applications/ts3.png b/ch6/applications/ts3.png
new file mode 100644
index 0000000..5491e19
Binary files /dev/null and b/ch6/applications/ts3.png differ
diff --git a/ch6/applications/ts4.png b/ch6/applications/ts4.png
new file mode 100644
index 0000000..03b8cb5
Binary files /dev/null and b/ch6/applications/ts4.png differ
diff --git a/ch6/applications/ts5.png b/ch6/applications/ts5.png
new file mode 100644
index 0000000..5fa874b
Binary files /dev/null and b/ch6/applications/ts5.png differ
diff --git a/ch6/applications/ts6.png b/ch6/applications/ts6.png
new file mode 100644
index 0000000..51e4353
Binary files /dev/null and b/ch6/applications/ts6.png differ
diff --git a/ch6/applications/ts7.png b/ch6/applications/ts7.png
new file mode 100644
index 0000000..11d51f5
Binary files /dev/null and b/ch6/applications/ts7.png differ
diff --git a/ch6/applications/ts8.png b/ch6/applications/ts8.png
new file mode 100644
index 0000000..42235a2
Binary files /dev/null and b/ch6/applications/ts8.png differ
diff --git a/ch6/concept/README.md b/ch6/concept/README.md
new file mode 100644
index 0000000..38bb136
--- /dev/null
+++ b/ch6/concept/README.md
@@ -0,0 +1,83 @@
+# 图的基本概念
+
+## 1. 无向图 & 有向图
+
+![图2](graph2.png)
+
+## 2. 简单图 & 多重图
+
+![图3](graph3.png)
+
+## 3. 完全图
+
+- 无向完全图
+- 有向完全图
+
+![图4](graph4.png)
+
+## 4. 子图
+
+- 与原图相同也成为子图。
+- 只有顶点也是子图
+
+![图5](graph5.png)
+
+![图5-2](graph5-2.png)
+
+## 5. 连通 & 强连通
+
+![图6](graph6.png)
+
+## 6. 连通图 & 强连通图
+
+![图7](graph7.png)
+
+![图8](graph8.png)
+
+## 7. 连通分量 & 强连通分量
+
+![图9](graph9.png)
+
+![图10](graph10.png)
+
+![图11](graph11.png)
+
+## 8. 极小连通子图
+
+![图12](graph12.png)
+
+## 9. 生成树、生成森林
+
+![图13](graph13.png)
+
+![图14](graph14.png)
+
+## 10. 顶点的度
+
+![图15](graph15.png)
+
+![图15-2](graph15-2.png)
+
+## 11. 网
+
+![图16](graph16.png)
+
+## 12. 稠密图 & 稀疏图
+
+![图17](graph17.png)
+
+## 13. 有向树
+
+![图18](graph18.png)
+
+## 14. 路径
+
+![图19](graph19.png)
+
+## 15. 路径长度
+
+![图20](graph20.png)
+
+## 16. 回路
+
+![图21](graph21.png)
diff --git a/ch6/concept/graph10.png b/ch6/concept/graph10.png
new file mode 100644
index 0000000..6c97cc0
Binary files /dev/null and b/ch6/concept/graph10.png differ
diff --git a/ch6/concept/graph11.png b/ch6/concept/graph11.png
new file mode 100644
index 0000000..1abe98d
Binary files /dev/null and b/ch6/concept/graph11.png differ
diff --git a/ch6/concept/graph12.png b/ch6/concept/graph12.png
new file mode 100644
index 0000000..4e980ce
Binary files /dev/null and b/ch6/concept/graph12.png differ
diff --git a/ch6/concept/graph13.png b/ch6/concept/graph13.png
new file mode 100644
index 0000000..717a7c0
Binary files /dev/null and b/ch6/concept/graph13.png differ
diff --git a/ch6/concept/graph14.png b/ch6/concept/graph14.png
new file mode 100644
index 0000000..434249d
Binary files /dev/null and b/ch6/concept/graph14.png differ
diff --git a/ch6/concept/graph15-2.png b/ch6/concept/graph15-2.png
new file mode 100644
index 0000000..7eb0cb6
Binary files /dev/null and b/ch6/concept/graph15-2.png differ
diff --git a/ch6/concept/graph15.png b/ch6/concept/graph15.png
new file mode 100644
index 0000000..a00b0dd
Binary files /dev/null and b/ch6/concept/graph15.png differ
diff --git a/ch6/concept/graph16.png b/ch6/concept/graph16.png
new file mode 100644
index 0000000..b1b3a76
Binary files /dev/null and b/ch6/concept/graph16.png differ
diff --git a/ch6/concept/graph17.png b/ch6/concept/graph17.png
new file mode 100644
index 0000000..3917d94
Binary files /dev/null and b/ch6/concept/graph17.png differ
diff --git a/ch6/concept/graph18.png b/ch6/concept/graph18.png
new file mode 100644
index 0000000..c66d90c
Binary files /dev/null and b/ch6/concept/graph18.png differ
diff --git a/ch6/concept/graph19.png b/ch6/concept/graph19.png
new file mode 100644
index 0000000..86a258c
Binary files /dev/null and b/ch6/concept/graph19.png differ
diff --git a/ch6/concept/graph2.png b/ch6/concept/graph2.png
new file mode 100644
index 0000000..97f31a8
Binary files /dev/null and b/ch6/concept/graph2.png differ
diff --git a/ch6/concept/graph20.png b/ch6/concept/graph20.png
new file mode 100644
index 0000000..f95b353
Binary files /dev/null and b/ch6/concept/graph20.png differ
diff --git a/ch6/concept/graph21.png b/ch6/concept/graph21.png
new file mode 100644
index 0000000..f219550
Binary files /dev/null and b/ch6/concept/graph21.png differ
diff --git a/ch6/concept/graph3.png b/ch6/concept/graph3.png
new file mode 100644
index 0000000..f59e8d8
Binary files /dev/null and b/ch6/concept/graph3.png differ
diff --git a/ch6/concept/graph4.png b/ch6/concept/graph4.png
new file mode 100644
index 0000000..e604daa
Binary files /dev/null and b/ch6/concept/graph4.png differ
diff --git a/ch6/concept/graph5-2.png b/ch6/concept/graph5-2.png
new file mode 100644
index 0000000..eaef56c
Binary files /dev/null and b/ch6/concept/graph5-2.png differ
diff --git a/ch6/concept/graph5.png b/ch6/concept/graph5.png
new file mode 100644
index 0000000..ff07014
Binary files /dev/null and b/ch6/concept/graph5.png differ
diff --git a/ch6/concept/graph6.png b/ch6/concept/graph6.png
new file mode 100644
index 0000000..5946de0
Binary files /dev/null and b/ch6/concept/graph6.png differ
diff --git a/ch6/concept/graph7.png b/ch6/concept/graph7.png
new file mode 100644
index 0000000..b98b66e
Binary files /dev/null and b/ch6/concept/graph7.png differ
diff --git a/ch6/concept/graph8.png b/ch6/concept/graph8.png
new file mode 100644
index 0000000..a3cb927
Binary files /dev/null and b/ch6/concept/graph8.png differ
diff --git a/ch6/concept/graph9.png b/ch6/concept/graph9.png
new file mode 100644
index 0000000..54cded2
Binary files /dev/null and b/ch6/concept/graph9.png differ
diff --git a/ch6/graph.png b/ch6/graph.png
new file mode 100644
index 0000000..f5d986a
Binary files /dev/null and b/ch6/graph.png differ
diff --git a/ch6/operation/README.md b/ch6/operation/README.md
new file mode 100644
index 0000000..cbaf997
--- /dev/null
+++ b/ch6/operation/README.md
@@ -0,0 +1,41 @@
+# 图的基本操作
+
+## 1. 边是否存在
+
+![基本操作1](operation1.png)
+
+![基本操作2](operation2.png)
+
+## 2. 顶点的邻接边
+
+![基本操作3](operation3.png)
+
+![基本操作4](operation4.png)
+
+## 3. 插入顶点
+
+![基本操作5](operation5.png)
+
+## 4. 删除顶点
+
+![基本操作6](operation6.png)
+
+## 5. 增加边
+
+![基本操作7](operation7.png)
+
+![基本操作8](operation8.png)
+
+## 6. 删除边
+
+![基本操作9](operation9.png)
+
+![基本操作10](operation10.png)
+
+## 7. 第一条边和下一条边
+
+![基本操作11](operation11.png)
+
+## 8. 获取权值和设置权值
+
+![基本操作12](operation12.png)
diff --git a/ch6/operation/operation1.png b/ch6/operation/operation1.png
new file mode 100644
index 0000000..442c812
Binary files /dev/null and b/ch6/operation/operation1.png differ
diff --git a/ch6/operation/operation10.png b/ch6/operation/operation10.png
new file mode 100644
index 0000000..a393a88
Binary files /dev/null and b/ch6/operation/operation10.png differ
diff --git a/ch6/operation/operation11.png b/ch6/operation/operation11.png
new file mode 100644
index 0000000..656cf7e
Binary files /dev/null and b/ch6/operation/operation11.png differ
diff --git a/ch6/operation/operation12.png b/ch6/operation/operation12.png
new file mode 100644
index 0000000..4cbff23
Binary files /dev/null and b/ch6/operation/operation12.png differ
diff --git a/ch6/operation/operation2.png b/ch6/operation/operation2.png
new file mode 100644
index 0000000..b89f7af
Binary files /dev/null and b/ch6/operation/operation2.png differ
diff --git a/ch6/operation/operation3.png b/ch6/operation/operation3.png
new file mode 100644
index 0000000..39f987a
Binary files /dev/null and b/ch6/operation/operation3.png differ
diff --git a/ch6/operation/operation4.png b/ch6/operation/operation4.png
new file mode 100644
index 0000000..9160e48
Binary files /dev/null and b/ch6/operation/operation4.png differ
diff --git a/ch6/operation/operation5.png b/ch6/operation/operation5.png
new file mode 100644
index 0000000..c2c6d09
Binary files /dev/null and b/ch6/operation/operation5.png differ
diff --git a/ch6/operation/operation6.png b/ch6/operation/operation6.png
new file mode 100644
index 0000000..9bd69ed
Binary files /dev/null and b/ch6/operation/operation6.png differ
diff --git a/ch6/operation/operation7.png b/ch6/operation/operation7.png
new file mode 100644
index 0000000..3cfb3f8
Binary files /dev/null and b/ch6/operation/operation7.png differ
diff --git a/ch6/operation/operation8.png b/ch6/operation/operation8.png
new file mode 100644
index 0000000..4314d8d
Binary files /dev/null and b/ch6/operation/operation8.png differ
diff --git a/ch6/operation/operation9.png b/ch6/operation/operation9.png
new file mode 100644
index 0000000..6d32142
Binary files /dev/null and b/ch6/operation/operation9.png differ
diff --git a/ch6/storage/README.md b/ch6/storage/README.md
new file mode 100644
index 0000000..9fe5458
--- /dev/null
+++ b/ch6/storage/README.md
@@ -0,0 +1,79 @@
+# 图的存储结构
+
+## 1. 邻接矩阵法
+
+- $V=\{A,B,C,D,E\}$ 用一维数组存储。
+- $E=\{(A,B),(A,C),(A,E),(B,C),(C,D),(C,E)\}$ 用二维数组存储。
+
+二维数组行号表示起始端点，列号表示终止端点，值表示该边是否存在或该边的权重。二维数组又称为邻接矩阵。
+
+结点数为 $n$ 的图 $G=(V,E)$ 的邻接矩阵是 $n \times n$ 的。
+
+将 $G$ 的顶点编号为 $V_1,V_2,...,V_n$ （数组下标），若 $<V_i,V_j> \in E$，则 $A[i][j]=1$，否则 $A[i][j]=0$。
+
+$$
+A[i][j]=
+\begin{cases}
+  1,(V_i,V_j)或<V_i,V_j>是E(G)的边\\
+  0,(V_i,V_j)或<V_i,V_j>不是E(G)的边\\
+\end{cases}
+$$
+
+![邻接矩阵1](adjacency-matrix1.png)
+
+![邻接矩阵2](adjacency-matrix2.png)
+
+![邻接矩阵3](adjacency-matrix3.png)
+
+![邻接矩阵4](adjacency-matrix4.png)
+
+![邻接矩阵5](adjacency-matrix5.png)
+
+![邻接矩阵5-2](adjacency-matrix5-2.png)
+
+![邻接矩阵5-3](adjacency-matrix5-3.png)
+
+- 邻接矩阵法的空间复杂度为：$O(n^2)$，适用于稠密图。
+- 无向图的邻接矩阵为对称矩阵。
+- 无向图中第 $i$ 行（或第 $i$ 列）非 $0$ 元素（非正无穷）的个数为第 $i$ 个顶点的度。
+- 有向图中第 $i$ 行（第 $i$ 列）非 $0$ 元素（非正无穷）的个数为第 $i$ 个顶点的出度（入度）。
+
+![邻接矩阵6](adjacency-matrix6.png)
+
+![邻接矩阵7](adjacency-matrix7.png)
+
+## 2. 邻接表法
+
+邻接矩阵法存储稀疏图会有很多空间浪费。
+
+![邻接表1](adjacency-list1.png)
+
+![邻接表2](adjacency-list2.png)
+
+![邻接表3](adjacency-list3.png)
+
+![邻接表4](adjacency-list4.png)
+
+![邻接表5](adjacency-list5.png)
+
+![邻接表6](adjacency-list6.png)
+
+## 3. 十字链表
+
+在邻接表中寻找所有的出边（以该顶点为弧尾的弧）非常容易，但是寻找某个顶点的入边非常困难，需要遍历整个边表。
+
+![十字链表1](cross-list1.png)
+
+![十字链表2](cross-list2.png)
+
+![十字链表3](cross-list3.png)
+
+## 4. 邻接多重表
+
+![邻接多重表1](adjacency-multiple-list1.png)
+
+![邻接多重表2](adjacency-multiple-list2.png)
+
+![邻接多重表3](adjacency-multiple-list3.png)
+
+![邻接多重表4](adjacency-multiple-list4.png)
diff --git a/ch6/storage/adjacency-list1.png b/ch6/storage/adjacency-list1.png
new file mode 100644
index 0000000..776c0d0
Binary files /dev/null and b/ch6/storage/adjacency-list1.png differ
diff --git a/ch6/storage/adjacency-list2.png b/ch6/storage/adjacency-list2.png
new file mode 100644
index 0000000..2a16055
Binary files /dev/null and b/ch6/storage/adjacency-list2.png differ
diff --git a/ch6/storage/adjacency-list3.png b/ch6/storage/adjacency-list3.png
new file mode 100644
index 0000000..7f8ae6f
Binary files /dev/null and b/ch6/storage/adjacency-list3.png differ
diff --git a/ch6/storage/adjacency-list4.png b/ch6/storage/adjacency-list4.png
new file mode 100644
index 0000000..0843742
Binary files /dev/null and b/ch6/storage/adjacency-list4.png differ
diff --git a/ch6/storage/adjacency-list5.png b/ch6/storage/adjacency-list5.png
new file mode 100644
index 0000000..18678e5
Binary files /dev/null and b/ch6/storage/adjacency-list5.png differ
diff --git a/ch6/storage/adjacency-list6.png b/ch6/storage/adjacency-list6.png
new file mode 100644
index 0000000..e343791
Binary files /dev/null and b/ch6/storage/adjacency-list6.png differ
diff --git a/ch6/storage/adjacency-matrix1.png b/ch6/storage/adjacency-matrix1.png
new file mode 100644
index 0000000..0a71ca1
Binary files /dev/null and b/ch6/storage/adjacency-matrix1.png differ
diff --git a/ch6/storage/adjacency-matrix2.png b/ch6/storage/adjacency-matrix2.png
new file mode 100644
index 0000000..32d1cd7
Binary files /dev/null and b/ch6/storage/adjacency-matrix2.png differ
diff --git a/ch6/storage/adjacency-matrix3.png b/ch6/storage/adjacency-matrix3.png
new file mode 100644
index 0000000..f3a95dd
Binary files /dev/null and b/ch6/storage/adjacency-matrix3.png differ
diff --git a/ch6/storage/adjacency-matrix4.png b/ch6/storage/adjacency-matrix4.png
new file mode 100644
index 0000000..77a20c9
Binary files /dev/null and b/ch6/storage/adjacency-matrix4.png differ
diff --git a/ch6/storage/adjacency-matrix5-2.png b/ch6/storage/adjacency-matrix5-2.png
new file mode 100644
index 0000000..27c2402
Binary files /dev/null and b/ch6/storage/adjacency-matrix5-2.png differ
diff --git a/ch6/storage/adjacency-matrix5-3.png b/ch6/storage/adjacency-matrix5-3.png
new file mode 100644
index 0000000..d273ec6
Binary files /dev/null and b/ch6/storage/adjacency-matrix5-3.png differ
diff --git a/ch6/storage/adjacency-matrix5.png b/ch6/storage/adjacency-matrix5.png
new file mode 100644
index 0000000..e7e10e6
Binary files /dev/null and b/ch6/storage/adjacency-matrix5.png differ
diff --git a/ch6/storage/adjacency-matrix6.png b/ch6/storage/adjacency-matrix6.png
new file mode 100644
index 0000000..cc4d5ad
Binary files /dev/null and b/ch6/storage/adjacency-matrix6.png differ
diff --git a/ch6/storage/adjacency-matrix7.png b/ch6/storage/adjacency-matrix7.png
new file mode 100644
index 0000000..57c2031
Binary files /dev/null and b/ch6/storage/adjacency-matrix7.png differ
diff --git a/ch6/storage/adjacency-multiple-list1.png b/ch6/storage/adjacency-multiple-list1.png
new file mode 100644
index 0000000..38159b9
Binary files /dev/null and b/ch6/storage/adjacency-multiple-list1.png differ
diff --git a/ch6/storage/adjacency-multiple-list2.png b/ch6/storage/adjacency-multiple-list2.png
new file mode 100644
index 0000000..98398e9
Binary files /dev/null and b/ch6/storage/adjacency-multiple-list2.png differ
diff --git a/ch6/storage/adjacency-multiple-list3.png b/ch6/storage/adjacency-multiple-list3.png
new file mode 100644
index 0000000..0d62bf8
Binary files /dev/null and b/ch6/storage/adjacency-multiple-list3.png differ
diff --git a/ch6/storage/adjacency-multiple-list4.png b/ch6/storage/adjacency-multiple-list4.png
new file mode 100644
index 0000000..352a1b4
Binary files /dev/null and b/ch6/storage/adjacency-multiple-list4.png differ
diff --git a/ch6/storage/cross-list1.png b/ch6/storage/cross-list1.png
new file mode 100644
index 0000000..66886c0
Binary files /dev/null and b/ch6/storage/cross-list1.png differ
diff --git a/ch6/storage/cross-list2.png b/ch6/storage/cross-list2.png
new file mode 100644
index 0000000..704821f
Binary files /dev/null and b/ch6/storage/cross-list2.png differ
diff --git a/ch6/storage/cross-list3.png b/ch6/storage/cross-list3.png
new file mode 100644
index 0000000..f574d3c
Binary files /dev/null and b/ch6/storage/cross-list3.png differ
diff --git a/ch6/traversal/README.md b/ch6/traversal/README.md
new file mode 100644
index 0000000..c061611
--- /dev/null
+++ b/ch6/traversal/README.md
@@ -0,0 +1,41 @@
+# 图的遍历
+
+## 1. 广度优先搜索
+
+![广度优先搜索1](bfs1.png)
+
+![广度优先搜索2](bfs2.png)
+
+![广度优先搜索3](bfs3.png)
+
+![广度优先搜索4](bfs4.png)
+
+![广度优先搜索5](bfs5.png)
+
+![广度优先搜索6](bfs6.png)
+
+![广度优先搜索7](bfs7.png)
+
+## 2. 深度优先搜索
+
+![深度优先搜索1](dfs1.png)
+
+![深度优先搜索2](dfs2.png)
+
+![深度优先搜索3](dfs3.png)
+
+![深度优先搜索4](dfs4.png)
+
+![深度优先搜索5](dfs5.png)
+
+![深度优先搜索6](dfs6.png)
+
+## 3. 遍历与连通性问题
+
+![深度优先搜索7](dfs7.png)
+
+![深度优先搜索8](dfs8.png)
+
+- 有向图中没有上述两个结论，
+
+![深度优先搜索9](dfs9.png)
diff --git a/ch6/traversal/bfs1.png b/ch6/traversal/bfs1.png
new file mode 100644
index 0000000..c796cd2
Binary files /dev/null and b/ch6/traversal/bfs1.png differ
diff --git a/ch6/traversal/bfs2.png b/ch6/traversal/bfs2.png
new file mode 100644
index 0000000..8b480f9
Binary files /dev/null and b/ch6/traversal/bfs2.png differ
diff --git a/ch6/traversal/bfs3.png b/ch6/traversal/bfs3.png
new file mode 100644
index 0000000..61365d0
Binary files /dev/null and b/ch6/traversal/bfs3.png differ
diff --git a/ch6/traversal/bfs4.png b/ch6/traversal/bfs4.png
new file mode 100644
index 0000000..1d4a0e7
Binary files /dev/null and b/ch6/traversal/bfs4.png differ
diff --git a/ch6/traversal/bfs5.png b/ch6/traversal/bfs5.png
new file mode 100644
index 0000000..3d05945
Binary files /dev/null and b/ch6/traversal/bfs5.png differ
diff --git a/ch6/traversal/bfs6.png b/ch6/traversal/bfs6.png
new file mode 100644
index 0000000..1cdbdbe
Binary files /dev/null and b/ch6/traversal/bfs6.png differ
diff --git a/ch6/traversal/bfs7.png b/ch6/traversal/bfs7.png
new file mode 100644
index 0000000..255d0a6
Binary files /dev/null and b/ch6/traversal/bfs7.png differ
diff --git a/ch6/traversal/dfs1.png b/ch6/traversal/dfs1.png
new file mode 100644
index 0000000..64e8de5
Binary files /dev/null and b/ch6/traversal/dfs1.png differ
diff --git a/ch6/traversal/dfs2.png b/ch6/traversal/dfs2.png
new file mode 100644
index 0000000..82d6c7f
Binary files /dev/null and b/ch6/traversal/dfs2.png differ
diff --git a/ch6/traversal/dfs3.png b/ch6/traversal/dfs3.png
new file mode 100644
index 0000000..9408dc1
Binary files /dev/null and b/ch6/traversal/dfs3.png differ
diff --git a/ch6/traversal/dfs4.png b/ch6/traversal/dfs4.png
new file mode 100644
index 0000000..e51f30d
Binary files /dev/null and b/ch6/traversal/dfs4.png differ
diff --git a/ch6/traversal/dfs5.png b/ch6/traversal/dfs5.png
new file mode 100644
index 0000000..b455bc4
Binary files /dev/null and b/ch6/traversal/dfs5.png differ
diff --git a/ch6/traversal/dfs6.png b/ch6/traversal/dfs6.png
new file mode 100644
index 0000000..d079f41
Binary files /dev/null and b/ch6/traversal/dfs6.png differ
diff --git a/ch6/traversal/dfs7.png b/ch6/traversal/dfs7.png
new file mode 100644
index 0000000..fecf315
Binary files /dev/null and b/ch6/traversal/dfs7.png differ
diff --git a/ch6/traversal/dfs8.png b/ch6/traversal/dfs8.png
new file mode 100644
index 0000000..c8e523a
Binary files /dev/null and b/ch6/traversal/dfs8.png differ
diff --git a/ch6/traversal/dfs9.png b/ch6/traversal/dfs9.png
new file mode 100644
index 0000000..be65c93
Binary files /dev/null and b/ch6/traversal/dfs9.png differ