diff --git a/algorithm-leetcode/pom.xml b/algorithm-leetcode/pom.xml
index 55db042..c72cdaf 100644
--- a/algorithm-leetcode/pom.xml
+++ b/algorithm-leetcode/pom.xml
@@ -12,4 +12,12 @@
     <artifactId>algorithm-leetcode</artifactId>
 
 
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+        </dependency>
+    </dependencies>
+
 </project>
\ No newline at end of file
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/AddTwoNumbers.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/AddTwoNumbers.java
new file mode 100644
index 0000000..b49742b
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/AddTwoNumbers.java
@@ -0,0 +1,88 @@
+package com.wxboot.algorithm.leetcode;
+
+/*
+ * @lc app=leetcode.cn id=2 lang=java
+ *
+ * [2] 两数相加
+ */
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode(int x) { val = x; }
+ * }
+ */
+public class AddTwoNumbers {
+
+    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {        
+        ListNode sumNode = new ListNode(0);  
+        ListNode sumNext = sumNode;
+        ListNode prev = null;
+        while (l1 != null || l2 != null) {           
+            int sum = sumNext.val;
+
+            if (l1 != null) {
+                sum += l1.val;
+                l1 = l1.next;
+            }
+
+            if (l2 != null) {
+                sum += l2.val;
+                l2 = l2.next;
+            }
+
+            sumNext.val = sum % 10;
+            sumNext.next = new ListNode(sum / 10);
+            prev = sumNext;
+            sumNext = sumNext.next;   
+        }
+        if (sumNext.val == 0) {
+            prev.next = null;
+            sumNext = null;
+        }
+
+        return sumNode;
+    }
+   
+    /**
+     * l1 l2 按自然数顺序排列相加，需先将l1 l2 反转，结果反转
+     * 输入：(3 -> 4 -> 2) + (4 -> 6 -> 5)
+     * 输出：8 -> 0 -> 7
+     * 原因：342 + 465 = 807
+     * @param l1
+     * @param l2
+     * @return
+     */
+    /* 
+    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+        l1 = converseList(l1);
+        l2 = converseList(l2);
+        System.out.println(l1.val);
+        ...
+    
+    }
+
+    public ListNode converseList(ListNode head) {
+        if (head == null) return head;
+        ListNode prev = null;
+        ListNode next = null;
+        while(head.next != null) {
+            next = head.next;
+            head.next = prev;
+            prev = head;
+            head = next;
+        }
+        return head;
+    }
+    */
+}
+
+class ListNode {
+    int val;
+    ListNode next;
+
+    ListNode(int x) {
+        val = x;
+    }
+}
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/IntIsPalindrome.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/IntIsPalindrome.java
new file mode 100644
index 0000000..f09da17
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/IntIsPalindrome.java
@@ -0,0 +1,43 @@
+package com.wxboot.algorithm.leetcode;
+
+public class IntIsPalindrome {
+
+    public boolean isPalindrome(int x) {
+        if (x < 0) {
+            return false;
+        }
+        if (x < 10) {
+            return true;
+        }
+
+        long y = reverseTwo(x);
+        return x == y;
+    }
+
+    public long reverseTwo(int x) {
+        int quotient = x;
+        // 54321 -> 5432 1 -> 543 2 -> 54 3 -> 5 4-> 0 5 
+        long y = 0;
+        while (quotient > 0) {
+            y = quotient%10 + y*10;
+            quotient = quotient/10;
+        }
+        return y > Integer.MAX_VALUE ? 0 : y;
+    }
+
+    public long reverseOne(int x) {        
+        String s = String.valueOf(x);
+        char[] arr = s.toCharArray();
+        // 12 1 123 1 1234 2 
+        int mid = (arr.length / 2);
+        for (int i = 0; i < mid; i++) {
+            char temp = arr[i];
+            arr[i] = arr[arr.length - i - 1];
+            arr[arr.length - i - 1] = temp;
+        }
+
+        long y = Long.valueOf(String.valueOf(arr));
+        return y > Integer.MAX_VALUE ? 0 : y;
+    }
+
+}
\ No newline at end of file
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/LengthOfLongestSubstring.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/LengthOfLongestSubstring.java
new file mode 100644
index 0000000..66dba6b
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/LengthOfLongestSubstring.java
@@ -0,0 +1,41 @@
+package com.wxboot.algorithm.leetcode;
+
+import java.util.stream.IntStream;
+
+public class LengthOfLongestSubstring {
+
+
+    private int lengthOfLongestSubstring(String s) {
+        if (s.length() == 1) {
+            return 1;
+        }
+
+        int[] bucket = new int[128];
+        // 使用原生 for 速度会更快 8ms
+        for (int i = 0; i < bucket.length; i++) {
+            bucket[(char) i] = -1;
+        }
+        // 100ms
+        // IntStream.iterate(0, n -> n + 1).limit(127).forEach(n -> bucket[n] = -1);
+
+        char[] arr = s.toCharArray();
+        int left = -1;
+        int max = 0;
+        for (int i = 0; i < arr.length; i++) {
+            int cur = bucket[arr[i]];
+            if (cur != -1) {
+                left = cur > left ? cur : left;
+            }
+
+            bucket[arr[i]] = i;
+            max = getMax(max, i - left);
+        }
+
+        return max;
+    }
+
+    private int getMax(int x, int y) {
+        return x > y ? x : y;
+    }
+
+}
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/LongestCommonPrefix.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/LongestCommonPrefix.java
new file mode 100644
index 0000000..424e200
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/LongestCommonPrefix.java
@@ -0,0 +1,94 @@
+package com.wxboot.algorithm.leetcode;
+
+import org.junit.Test;
+
+/**
+ * Copyright ©2017-2018, wxboot.com. All Rights Reserved.
+ *
+ * @author 娱乐不在线 wxboot.com
+ * @version 1.0.0
+ * @Description:
+ * @date Created in 2019/5/19 17:36
+ */
+public class LongestCommonPrefix {
+
+
+    @Test
+    public void testOne() {
+        String[] arr = {"abcddddb", "abcdeggg", "abadeggg"};
+
+        String prefix = getPrefixStartCmp(arr);
+        System.out.println("prefix : " + prefix);
+    }
+
+    /**
+     * 貌似正向比对比逆向比对要快一些
+     *
+     * @param arr
+     * @return
+     */
+    public String getPrefixStartCmp(String[] arr) {
+        if (arr.length == 0) {
+            return "";
+        }
+        if (arr.length == 1) {
+            return arr[0];
+        }
+
+        int last = arr[0].length();
+        for (int i = 0; i < arr.length - 1; i++) {
+            if (arr[i].length() == 0 || arr[i + 1].length() == 0) {
+                return "";
+            }
+
+            last = getMin(last, arr[i + 1].length());
+            for (int j = 0; j < last; j++) {
+                if (arr[i].charAt(j) != arr[i + 1].charAt(j)) {
+                    last = j;
+                }
+            }
+        }
+
+        char[] prefixArr = new char[last];
+        for (int i = 0; i < last; i++) {
+            prefixArr[i] = arr[0].charAt(i);
+        }
+
+        return String.valueOf(prefixArr);
+    }
+
+    public String getPrefixEndCmp(String[] arr) {
+        if (arr.length == 0) {
+            return "";
+        }
+        if (arr.length == 1) {
+            return arr[0];
+        }
+
+        int last = arr[0].length();
+        for (int i = 0; i < arr.length - 1; i++) {
+            if (arr[i].length() == 0 || arr[i + 1].length() == 0) {
+                return "";
+            }
+
+            last = getMin(last, arr[i + 1].length());
+
+            for (int j = last - 1; j >= 0; j--) {
+                if (arr[i].charAt(j) != arr[i + 1].charAt(j)) {
+                    last = j;
+                }
+            }
+        }
+
+        char[] prefixArr = new char[last];
+        for (int i = 0; i < last; i++) {
+            prefixArr[i] = arr[0].charAt(i);
+        }
+
+        return String.valueOf(prefixArr);
+    }
+
+    public int getMin(int x, int y) {
+        return x > y ? y : x;
+    }
+}
\ No newline at end of file
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/ReverseNumber.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/ReverseNumber.java
new file mode 100644
index 0000000..7220211
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/ReverseNumber.java
@@ -0,0 +1,26 @@
+package com.wxboot.algorithm.leetcode;
+
+public class ReverseNumber {
+
+    
+    private int reverseNumber(int number) {
+        String s = String.valueOf(number);
+        char[] arr = s.toCharArray();
+        char minus = '-';
+
+        int start = 0;
+        if (arr[0] == minus) {
+            start = 1;
+        }
+        int mid = ((arr.length - start) / 2);
+        int right = arr.length - 1;
+        for (int i = start; i <= mid && right >= mid; i++, right--) {
+            char temp = arr[i];
+            arr[i] = arr[right];
+            arr[right] = temp;
+        }
+        Long result = Long.parseLong(String.valueOf(arr));
+        return result > Integer.MAX_VALUE || result < Integer.MIN_VALUE ? 0 : result.intValue();
+    }
+
+}
\ No newline at end of file
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/RomanToInt.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/RomanToInt.java
new file mode 100644
index 0000000..e1b0964
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/RomanToInt.java
@@ -0,0 +1,73 @@
+package com.wxboot.algorithm.leetcode;
+
+import org.junit.Test;
+
+/**
+ * Copyright ©2017-2018, wxboot.com. All Rights Reserved.
+ *
+ * @author 娱乐不在线 wxboot.com
+ * @version 1.0.0
+ * @Description:
+ * @date Created in 2019/5/19 16:59
+ */
+public class RomanToInt {
+
+    @Test
+    public void testOne() {
+        int num = romanToInt("D");
+        System.out.println("num : " + num);
+
+    }
+
+    public int romanToInt(String s) {
+        char[] x = new char[]{'M', 'D', 'C', 'L', 'X', 'V', 'I'};
+
+        int num = convert(s);
+
+        return num;
+    }
+
+    public int convert(String s) {
+        int[] romanArr = new int[127];
+        romanArr['M'] = 1000;
+        romanArr['D'] = 500;
+        romanArr['C'] = 100;
+        romanArr['L'] = 50;
+        romanArr['X'] = 10;
+        romanArr['V'] = 5;
+        romanArr['I'] = 1;
+
+        char[] arr = s.toCharArray();
+        int prev = romanArr[arr[0]];
+
+        if (arr.length == 1) {
+            return prev;
+        }
+
+        int num = 0;
+        for (int i = 1; i < arr.length; i++) {
+            int cur = romanArr[arr[i]];
+
+            if (prev < cur) {
+                num += cur - prev;
+                if (i < arr.length - 1) {
+                    prev = romanArr[arr[++i]];
+                } else {
+                    prev = 0;
+                }
+
+            } else {
+                num += prev;
+                prev = cur;
+            }
+
+            if (i == arr.length - 1) {
+                num += prev;
+            }
+            System.out.println(arr[i] + ":" + prev + ":" + cur);
+        }
+
+        return num;
+    }
+
+}
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/SymbolIsValid.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/SymbolIsValid.java
new file mode 100644
index 0000000..d16574f
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/SymbolIsValid.java
@@ -0,0 +1,55 @@
+package com.wxboot.algorithm.leetcode;
+
+import org.junit.Test;
+
+import java.util.Stack;
+
+/**
+ * Copyright ©2017-2018, wxboot.com. All Rights Reserved.
+ *
+ * @author 娱乐不在线 wxboot.com
+ * @version 1.0.0
+ * @Description:
+ * @date Created in 2019/5/20 0:47
+ */
+public class SymbolIsValid {
+
+    @Test
+    public void testOne() {
+        System.out.println(isValid("()"));
+    }
+
+    public boolean isValid(String s) {
+        char[] arr = s.toCharArray();
+
+        Stack<Character> stack = new Stack<>();
+
+        boolean isValid = false;
+        for (int i = 0; i < arr.length; i++) {
+            if (arr[i] == '{') {
+                stack.push('}');
+            }
+            if (arr[i] == '(') {
+                stack.push(')');
+            }
+            if (arr[i] == '[') {
+                stack.push(']');
+            }
+
+            if (arr[i] == '}' || arr[i] == ')' || arr[i] == ']') {
+                if (stack.isEmpty()) {
+                    return false;
+                }
+
+                isValid = stack.pop() == arr[i];
+                if (isValid) {
+                    continue;
+                }
+                return false;
+            }
+        }
+        return isValid;
+    }
+
+}
+
diff --git a/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/TwoSum.java b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/TwoSum.java
new file mode 100644
index 0000000..1417db6
--- /dev/null
+++ b/algorithm-leetcode/src/main/java/com.wxboot.algorithm.leetcode/TwoSum.java
@@ -0,0 +1,27 @@
+package com.wxboot.algorithm.leetcode;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/*
+ * @lc app=leetcode.cn id=1 lang=java
+ *
+ * [1] 两数之和
+ */
+public class TwoSum {
+
+    public int[] twoSum(int[] nums, int target) {
+        Map<Integer, Integer> map = new HashMap<>(nums.length);    
+        for (int i = 0; i < nums.length; i++) {                                
+            Integer index = map.get(target - nums[i]);
+            if (Objects.nonNull(index)) {
+                return new int[]{index, i};
+            }
+            map.put(nums[i], i);
+        }
+        return null;
+    }
+
+}
+
diff --git a/pom.xml b/pom.xml
index caabc1f..fe74cb3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -8,11 +8,10 @@
 	<version>0.0.1-SNAPSHOT</version>
 	<modules>
 		<module>algorithm-leetcode</module>
-		<module>algorithm-leetcode</module>
 	</modules>
 	<packaging>pom</packaging>
 
-	<name>algorithm</name>
+	<name>algorithm-parent</name>
 	<description>算法题解过程</description>
 
 	<properties>