Add files via upload

Author: assassint2017

Restore IP Addresses/Restore_IP_Addresses.cpp

@@ -0,0 +1,48 @@
+// 典型的DFS
+
+// Runtime: 0 ms, faster than 100.00% of C++ online submissions for Restore IP Addresses.
+// Memory Usage: 8.5 MB, less than 91.67% of C++ online submissions for Restore IP Addresses.
+
+class Solution 
+{
+public:
+    vector<string> restoreIpAddresses(string s) 
+    {
+        vector<string> res;
+        
+        getCandidate(s, "", res, 4);
+        
+        return res;
+    }
+private:
+    void getCandidate(string input, string curStr, vector<string>& res, int numOfDigit)
+    {
+        // 边界条件处理
+        if (input.length() < numOfDigit || input.length() > numOfDigit * 3)
+            return ;
+        
+        if (numOfDigit == 1)
+        {
+            if (atoi(input.c_str()) <= 255)
+            {
+                if (input.length() == 1)
+                    res.push_back(curStr + input);
+                else if (input[0] != '0')
+                    res.push_back(curStr + input);
+            }
+            return ;
+        }
+        
+        for (int i = 1; i <= 3; ++i)
+        {
+            if (input.length() < i) return ;
+            string substr = input.substr(0, i);
+            
+            if (i < 3 || atoi(substr.c_str()) <= 255)
+                getCandidate(input.substr(i), curStr + substr + '.', res, numOfDigit - 1);
+            
+            if (input[0] == '0')
+                break;
+        }
+    }
+};