feat: add 003

Author: Blankj

README.md

@@ -47,6 +47,7 @@
 |#|Title|Tag|
 |:------------- |:------------- |:------------- |
 |2|[Add Two Numbers][002]|Linked List, Math|
+|3|[Longest Substring Without Repeating Characters][003]|Hash Table, Two Pointers, String|
 |8|[String to Integer (atoi)][008]|Math, String|
 |19|[Remove Nth Node From End of List][019]|Linked List, Two Pointers|
 
@@ -97,6 +98,7 @@
 [122]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/122/README.md
 
 [002]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/002/README.md
+[003]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/003/README.md
 [008]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/008/README.md
 [019]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/019/README.md
 

note/003/README.md

@@ -0,0 +1,51 @@
+# [Longest Substring Without Repeating Characters][title]
+
+## Description
+
+Given a string, find the length of the **longest substring** without repeating characters.
+
+**Examples:**
+
+Given `"abcabcbb"`, the answer is `"abc"`, which the length is 3.
+
+Given `"bbbbb"`, the answer is `"b"`, with the length of 1.
+
+Given `"pwwkew"`, the answer is `"wke"`, with the length of 3. Note that the answer must be a **substring**, `"pwke"` is a *subsequence*and not a substring.
+
+**Tags:** Hash Table, Two Pointers, String
+
+
+## 思路
+
+题意是计算不带重复字符的最长子字符串的长度，开辟一个hash数组来存储该字符上次出现的位置，比如`hash[a] = 3`就是代表`a`字符前一次出现的索引在3，遍历该字符串，获取到上次出现的最大索引（只能向前，不能退后），与当前的索引做差获取的就是本次所需长度，从中迭代出最大值就是最终答案。
+
+``` java
+class Solution {
+    public int lengthOfLongestSubstring(String s) {
+        int len;
+        if (s == null || (len = s.length()) == 0) return 0;
+        int preP = 0, max = 0;
+        int[] hash = new int[128];
+        for (int i = 0; i < len; ++i) {
+            char c = s.charAt(i);
+            if (hash[c] > preP) {
+                preP = hash[c];
+            }
+            int l = i - preP + 1;
+            hash[c] = i + 1;
+            if (l > max) max = l;
+        }
+        return max;
+    }
+}
+```
+
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我GitHub上的LeetCode题解：[awesome-java-leetcode][ajl]
+
+
+
+[title]: https://leetcode.com/problems/longest-substring-without-repeating-characters
+[ajl]: https://github.com/Blankj/awesome-java-leetcode

project/leetcode/.idea/workspace.xml

@@ -2,8 +2,6 @@
 
 import com.blankj.structure.ListNode;
 
-import java.util.Arrays;
-
 /**
  * <pre>
  *     author: Blankj
@@ -13,15 +11,32 @@
  * </pre>
  */
 public class Solution {
-
     public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
-
+        ListNode node = new ListNode(0);
+        ListNode n1 = l1, n2 = l2, t = node;
+        int sum = 0;
+        while (n1 != null || n2 != null) {
+            sum /= 10;
+            if (n1 != null) {
+                sum += n1.val;
+                n1 = n1.next;
+            }
+            if (n2 != null) {
+                sum += n2.val;
+                n2 = n2.next;
+            }
+            t.next = new ListNode(sum % 10);
+            t = t.next;
+        }
+        if (sum / 10 != 0) t.next = new ListNode(1);
+        return node.next;
     }
 
-
     public static void main(String[] args) {
         Solution solution = new Solution();
-
-        System.out.println(Arrays.toString(solution.addTwoNumbers(nums, target)));
+        ListNode.print(solution.addTwoNumbers(
+                ListNode.createTestData("[2,4,3]"),
+                ListNode.createTestData("[5,6,4]")
+        ));
     }
 }

project/leetcode/out/production/leetcode/com/blankj/easy/_122/Solution.class

@@ -0,0 +1,36 @@
+package com.blankj.medium._003;
+
+/**
+ * <pre>
+ *     author: Blankj
+ *     blog  : http://blankj.com
+ *     time  : 2017/10/11
+ *     desc  :
+ * </pre>
+ */
+public class Solution {
+    public int lengthOfLongestSubstring(String s) {
+        int len;
+        if (s == null || (len = s.length()) == 0) return 0;
+        int preP = 0, max = 0;
+        int[] hash = new int[128];
+        for (int i = 0; i < len; ++i) {
+            char c = s.charAt(i);
+            if (hash[c] > preP) {
+                preP = hash[c];
+            }
+            int l = i - preP + 1;
+            hash[c] = i + 1;
+            if (l > max) max = l;
+        }
+        return max;
+    }
+
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+        System.out.println(solution.lengthOfLongestSubstring("abcabcbb"));
+        System.out.println(solution.lengthOfLongestSubstring("bbbbb"));
+        System.out.println(solution.lengthOfLongestSubstring("pwwkew"));
+        System.out.println(solution.lengthOfLongestSubstring("Abcabcbb"));
+    }
+}