Create 3_puck.cpp

LeetCode-CN/3_puck.cpp

@@ -0,0 +1,35 @@
+#include <algorithm>
+#include <string>
+#include <set>
+using std::string;
+class Solution
+{
+  public:
+    int lengthOfLongestSubstring(string s)
+    {
+        int result{};
+        for (std::size_t i{}; i < s.size(); ++i)
+        {
+            string tmp_str = s.substr(i);
+            int cu_length{};
+            std::set<char> set_except;
+            
+            for (auto ch : tmp_str)
+            {
+                if (set_except.end() == set_except.find(ch))
+                {
+                    set_except.insert(ch);
+                    ++cu_length;
+                }
+                else
+                {
+                    break;
+                }
+            }
+
+            result = std::max(result, cu_length);
+        }
+
+        return result;
+    }
+};