Create Solution.cpp

Author: zouwx2cs

solution/0093.Restore IP Addresses/Solution.cpp

@@ -0,0 +1,54 @@
+class Solution {
+private:
+    inline string Check(string &s, int widths[])
+    {
+        widths[1] += widths[0] ;
+        widths[2] += widths[1] ;
+        widths[3] = s.length() - widths[2] ;
+        
+        if (widths[3] < 1 || widths[3] > 3 )
+            return "" ;
+        
+        widths[3] = s.length() ;
+        
+        for (int seg = 0; seg < 4; ++seg)
+        {
+            int num = 0 ;
+            for (int i = (seg == 0? 0: widths[seg-1]); i < widths[seg]; ++i)
+            {
+                num *= 10 ;
+                num += s[i] - '0' ;
+            }
+            if (num > 255)
+                return "" ;
+            
+            int w = widths[seg] - (seg == 0? 0: widths[seg-1]) ;
+            if (w == 3 && num < 100)
+                return "" ;
+            if (w == 2 && num < 10)
+                return "" ;
+        }
+        string res = s ;
+        for (int i = 2; i >= 0; --i)
+            res.insert(widths[i], ".") ;
+        
+        return res ;
+    }
+public:
+    vector<string> restoreIpAddresses(string s) {
+        int widths[4] ;
+        vector<string> res ;
+        for (int i = 0; i < 27; ++i)
+        {
+            widths[0] = 1 + i%3 ;
+            widths[1] = 1 + i/3%3 ;
+            widths[2] = 1 + i/9 ;
+            
+            string tmp = Check(s, widths) ;
+            if (tmp.size() != 0)
+                res.push_back(tmp) ;
+        }
+        
+        return res; 
+    }
+};