add 0390 folder & cpp(12ms) version

Author: zouwx2cs

solution/0393.UTF-8 Validation/Solution.cpp

@@ -0,0 +1,33 @@
+class Solution {
+public:
+    bool validUtf8(vector<int>& data) {
+        const unsigned modeContinue = 0xc0 ;
+        
+        int conti = 0 ;
+        for (auto it = data.begin(); it < data.end(); ++it)
+        {
+            
+            if (0 == conti) // 首字节
+            {
+                if (*it < 0x80)
+                    continue ;
+                else if (*it < 0xe0)
+                    conti = 1 ;
+                else if (*it < 0xf0)
+                    conti = 2 ;
+                else if (*it < 0xf8)
+                    conti = 3 ;
+                else
+                    return false ;
+            }
+            else // 后续字节
+            {
+                --conti ;
+                if ((*it & modeContinue) != 0x80)
+                    return false ;
+            }
+        }
+        
+        return 0 == conti ;
+    }
+};