diff --git a/src/class32/Code01_IndexTree.java b/src/class32/Code01_IndexTree.java
new file mode 100644
index 0000000..f7d5eca
--- /dev/null
+++ b/src/class32/Code01_IndexTree.java
@@ -0,0 +1,77 @@
+package class32;
+
+public class Code01_IndexTree {
+
+	public static class IndexTree {
+
+		private int[] tree;
+		private int N;
+
+		public IndexTree(int size) {
+			N = size;
+			tree = new int[N + 1];
+		}
+
+		public int sum(int index) {
+			int ret = 0;
+			while (index > 0) {
+				ret += tree[index];
+				index -= index & -index;
+			}
+			return ret;
+		}
+
+		public void add(int index, int d) {
+			while (index <= N) {
+				tree[index] += d;
+				index += index & -index;
+			}
+		}
+	}
+
+	public static class Right {
+		private int[] nums;
+		private int N;
+
+		public Right(int size) {
+			N = size + 1;
+			nums = new int[N + 1];
+		}
+
+		public int sum(int index) {
+			int ret = 0;
+			for (int i = 1; i <= index; i++) {
+				ret += nums[i];
+			}
+			return ret;
+		}
+
+		public void add(int index, int d) {
+			nums[index] += d;
+		}
+
+	}
+
+	public static void main(String[] args) {
+		int N = 100;
+		int V = 100;
+		int testTime = 2000000;
+		IndexTree tree = new IndexTree(N);
+		Right test = new Right(N);
+		System.out.println("test begin");
+		for (int i = 0; i < testTime; i++) {
+			int index = (int) (Math.random() * N) + 1;
+			if (Math.random() <= 0.5) {
+				int add = (int) (Math.random() * V);
+				tree.add(index, add);
+				test.add(index, add);
+			} else {
+				if (tree.sum(index) != test.sum(index)) {
+					System.out.println("Oops!");
+				}
+			}
+		}
+		System.out.println("test finish");
+	}
+
+}
diff --git a/src/class32/Code02_IndexTree2D.java b/src/class32/Code02_IndexTree2D.java
new file mode 100644
index 0000000..12bb6e2
--- /dev/null
+++ b/src/class32/Code02_IndexTree2D.java
@@ -0,0 +1,57 @@
+package class32;
+
+// 测试链接：https://leetcode.com/problems/range-sum-query-2d-mutable
+// 但这个题是付费题目
+// 提交时把类名、构造函数名从Code02_IndexTree2D改成NumMatrix
+public class Code02_IndexTree2D {
+	private int[][] tree;
+	private int[][] nums;
+	private int N;
+	private int M;
+
+	public Code02_IndexTree2D(int[][] matrix) {
+		if (matrix.length == 0 || matrix[0].length == 0) {
+			return;
+		}
+		N = matrix.length;
+		M = matrix[0].length;
+		tree = new int[N + 1][M + 1];
+		nums = new int[N][M];
+		for (int i = 0; i < N; i++) {
+			for (int j = 0; j < M; j++) {
+				update(i, j, matrix[i][j]);
+			}
+		}
+	}
+
+	private int sum(int row, int col) {
+		int sum = 0;
+		for (int i = row + 1; i > 0; i -= i & (-i)) {
+			for (int j = col + 1; j > 0; j -= j & (-j)) {
+				sum += tree[i][j];
+			}
+		}
+		return sum;
+	}
+
+	public void update(int row, int col, int val) {
+		if (N == 0 || M == 0) {
+			return;
+		}
+		int add = val - nums[row][col];
+		nums[row][col] = val;
+		for (int i = row + 1; i <= N; i += i & (-i)) {
+			for (int j = col + 1; j <= M; j += j & (-j)) {
+				tree[i][j] += add;
+			}
+		}
+	}
+
+	public int sumRegion(int row1, int col1, int row2, int col2) {
+		if (N == 0 || M == 0) {
+			return 0;
+		}
+		return sum(row2, col2) + sum(row1 - 1, col1 - 1) - sum(row1 - 1, col2) - sum(row2, col1 - 1);
+	}
+
+}
diff --git a/src/class32/Code03_AC1.java b/src/class32/Code03_AC1.java
new file mode 100644
index 0000000..a6874e5
--- /dev/null
+++ b/src/class32/Code03_AC1.java
@@ -0,0 +1,105 @@
+package class32;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class Code03_AC1 {
+
+	public static class Node {
+		public int end; // 有多少个字符串以该节点结尾
+		public Node fail;
+		public Node[] nexts;
+
+		public Node() {
+			end = 0;
+			fail = null;
+			nexts = new Node[26];
+		}
+	}
+
+	public static class ACAutomation {
+		private Node root;
+
+		public ACAutomation() {
+			root = new Node();
+		}
+
+		// 你有多少个匹配串，就调用多少次insert
+		public void insert(String s) {
+			char[] str = s.toCharArray();
+			Node cur = root;
+			int index = 0;
+			for (int i = 0; i < str.length; i++) {
+				index = str[i] - 'a';
+				if (cur.nexts[index] == null) {
+					Node next = new Node();
+					cur.nexts[index] = next;
+				}
+				cur = cur.nexts[index];
+			}
+			cur.end++;
+		}
+
+		public void build() {
+			Queue<Node> queue = new LinkedList<>();
+			queue.add(root);
+			Node cur = null;
+			Node cfail = null;
+			while (!queue.isEmpty()) {
+				cur = queue.poll(); // 父
+				for (int i = 0; i < 26; i++) { // 下级所有的路
+					if (cur.nexts[i] != null) { // 该路下有子节点
+						cur.nexts[i].fail = root; // 初始时先设置一个值
+						cfail = cur.fail;
+						while (cfail != null) { // cur不是头节点
+							if (cfail.nexts[i] != null) {
+								cur.nexts[i].fail = cfail.nexts[i];
+								break;
+							}
+							cfail = cfail.fail;
+						}
+						queue.add(cur.nexts[i]);
+					}
+				}
+			}
+		}
+
+		public int containNum(String content) {
+			char[] str = content.toCharArray();
+			Node cur = root;
+			Node follow = null;
+			int index = 0;
+			int ans = 0;
+			for (int i = 0; i < str.length; i++) {
+				index = str[i] - 'a';
+				while (cur.nexts[index] == null && cur != root) {
+					cur = cur.fail;
+				}
+				cur = cur.nexts[index] != null ? cur.nexts[index] : root;
+				follow = cur;
+				while (follow != root) {
+					if (follow.end == -1) {
+						break;
+					}
+					{ // 不同的需求，在这一段{ }之间修改
+						ans += follow.end;
+						follow.end = -1;
+					} // 不同的需求，在这一段{ }之间修改
+					follow = follow.fail;
+				}
+			}
+			return ans;
+		}
+
+	}
+
+	public static void main(String[] args) {
+		ACAutomation ac = new ACAutomation();
+		ac.insert("dhe");
+		ac.insert("he");
+		ac.insert("c");
+		ac.build();
+		System.out.println(ac.containNum("cdhe"));
+	}
+
+}
diff --git a/src/class32/Code04_AC2.java b/src/class32/Code04_AC2.java
new file mode 100644
index 0000000..fc915bc
--- /dev/null
+++ b/src/class32/Code04_AC2.java
@@ -0,0 +1,126 @@
+package class32;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+public class Code04_AC2 {
+
+	// 前缀树的节点
+	public static class Node {
+		// 如果一个node，end为空，不是结尾
+		// 如果end不为空，表示这个点是某个字符串的结尾，end的值就是这个字符串
+		public String end;
+		// 只有在上面的end变量不为空的时候，endUse才有意义
+		// 表示，这个字符串之前有没有加入过答案
+		public boolean endUse;
+		public Node fail;
+		public Node[] nexts;
+		public Node() {
+			endUse = false;
+			end = null;
+			fail = null;
+			nexts = new Node[26];
+		}
+	}
+
+	public static class ACAutomation {
+		private Node root;
+
+		public ACAutomation() {
+			root = new Node();
+		}
+
+		public void insert(String s) {
+			char[] str = s.toCharArray();
+			Node cur = root;
+			int index = 0;
+			for (int i = 0; i < str.length; i++) {
+				index = str[i] - 'a';
+				if (cur.nexts[index] == null) {
+					Node next = new Node();
+					cur.nexts[index] = next;
+				}
+				cur = cur.nexts[index];
+			}
+			cur.end = s;
+		}
+
+		public void build() {
+			Queue<Node> queue = new LinkedList<>();
+			queue.add(root);
+			Node cur = null;
+			Node cfail = null;
+			while (!queue.isEmpty()) {
+				// 当前节点弹出，
+				// 当前节点的所有后代加入到队列里去，
+				// 当前节点给它的子去设置fail指针
+				// cur -> 父亲
+				cur = queue.poll();
+				for (int i = 0; i < 26; i++) { // 所有的路
+					if (cur.nexts[i] != null) { // 找到所有有效的路
+						cur.nexts[i].fail = root; //
+						cfail = cur.fail;
+						while (cfail != null) {
+							if (cfail.nexts[i] != null) {
+								cur.nexts[i].fail = cfail.nexts[i];
+								break;
+							}
+							cfail = cfail.fail;
+						}
+						queue.add(cur.nexts[i]);
+					}
+				}
+			}
+		}
+
+		public List<String> containWords(String content) {
+			char[] str = content.toCharArray();
+			Node cur = root;
+			Node follow = null;
+			int index = 0;
+			List<String> ans = new ArrayList<>();
+			for (int i = 0; i < str.length; i++) {
+				index = str[i] - 'a'; // 路
+				// 如果当前字符在这条路上没配出来，就随着fail方向走向下条路径
+				while (cur.nexts[index] == null && cur != root) {
+					cur = cur.fail;
+				}
+				// 1) 现在来到的路径，是可以继续匹配的
+				// 2) 现在来到的节点，就是前缀树的根节点
+				cur = cur.nexts[index] != null ? cur.nexts[index] : root;
+				follow = cur;
+				while (follow != root) {
+					if(follow.endUse) {
+						break;
+					}
+					// 不同的需求，在这一段之间修改
+					if (follow.end != null) {
+						ans.add(follow.end);
+						follow.endUse = true;
+					}
+					// 不同的需求，在这一段之间修改
+					follow = follow.fail;
+				}
+			}
+			return ans;
+		}
+
+	}
+
+	public static void main(String[] args) {
+		ACAutomation ac = new ACAutomation();
+		ac.insert("dhe");
+		ac.insert("he");
+		ac.insert("abcdheks");
+		// 设置fail指针
+		ac.build();	
+		
+		List<String> contains = ac.containWords("abcdhekskdjfafhasldkflskdjhwqaeruv");
+		for (String word : contains) {
+			System.out.println(word);
+		}
+	}
+
+}