Create restore_ip_addresses.cpp

Author: avidLearnerInProgress

restore_ip_addresses.cpp

@@ -0,0 +1,37 @@
+//slow approach. I believe its related with concatenation on the fly. += 
+class Solution {
+    void getIPAddresses(vector<string> &temp, vector<string> &IPs, string &s, int index) {
+        if(index == s.length() && temp.size() == 4) {
+            string validIP = temp[0] + '.' + temp[1] + '.' + temp[2] + '.' + temp[3] ;
+            IPs.push_back(validIP);
+            return;
+        }
+
+        string tempStr = "";
+        for(int i = index ; i< s.length() && temp.size() < 4; i++) {
+            if(s[i] - '0' > 9) {
+                continue;
+            }
+            tempStr += s[i];
+            int tempInt = stoi(tempStr);
+            if(0 <= tempInt && tempInt <= 255) {
+                temp.push_back(tempStr);
+                getIPAddresses(temp, IPs, s, i+1);
+                temp.pop_back();
+            }
+            if(tempInt <= 0 || tempInt > 255) {
+                break;
+            }
+        }
+    }
+
+public:
+    vector<string> restoreIpAddresses(string s) {
+        vector<string> IPs;
+        vector<string> temp;
+        getIPAddresses(temp, IPs, s, 0);
+        return IPs;
+    }
+    
+  
+};