滑动窗口法，0003，无重复字符的最长子串

哈希表加上滑动窗口法

Author: moralok

README.md

@@ -4,7 +4,7 @@
 |----|----|----|----|
 |[0001](https://leetcode-cn.com/problems/two-sum/)|两数之和|简单|[top](top)|
 |[0002](https://leetcode-cn.com/problems/add-two-numbers/)|两数相加|中等|[top](top)|
-|[0003](https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/)|无重复字符的最长子串|中等|[top](top)|
+|[0003](https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/)|无重复字符的最长子串|中等|[top](top) [sliding window](sliding_window)|
 |[0005](https://leetcode-cn.com/problems/longest-palindromic-substring/)|最长回文子串|中等|[top](top)|
 |[0008](https://leetcode-cn.com/problems/string-to-integer-atoi/)|字符串转换整数 (atoi)|中等|[top](top)|
 |[0011](https://leetcode-cn.com/problems/container-with-most-water/)|盛最多水的容器|中等|[top](top)|

sliding_window/Lc0003Solution.java

@@ -0,0 +1,35 @@
+package sliding_window;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Lc0003Solution {
+    public int lengthOfLongestSubstring(String s) {
+        if (s == null || s.length() == 0) {
+            return 0;
+        }
+        int start = 0, ret = 0;
+        Map<Character, Integer> map = new HashMap<>();
+        for (int i = 0; i < s.length(); i++) {
+            char c = s.charAt(i);
+            if (map.containsKey(c)) {
+                start = Math.max(start, map.get(c) + 1);
+            }
+            ret = Math.max(ret, i - start + 1);
+            map.put(c, i);
+        }
+        return ret;
+    }
+
+    public static void main(String[] args) {
+        Lc0003Solution solution = new Lc0003Solution();
+        String s = "abcabc";
+        System.out.println(solution.lengthOfLongestSubstring(s));
+        s = "";
+        System.out.println(solution.lengthOfLongestSubstring(s));
+        s = "aaaa";
+        System.out.println(solution.lengthOfLongestSubstring(s));
+        s = "pwwkew";
+        System.out.println(solution.lengthOfLongestSubstring(s));
+    }
+}

sliding_window/README.md

@@ -0,0 +1,4 @@
+## Sliding Window
+|题号|题目|难度|在本目录|
+|----|----|----|----|
+|0003|无重复字符的最长子串|中等|是|