@@ -0,0 +1,796 @@
+public class Solution %7B%0A    private List%3CString%3E list;%0A    public List%3CString%3E restoreIpAddresses(String s) %7B%0A        list = new ArrayList%3CString%3E();%0A        backtrack(s, 0, 4, %22%22);%0A        return list;%0A    %7D%0A    %0A    private void backtrack(String s, int k, int n, String ret) %7B%0A        if(k == s.length() && n == 0) %7B%0A            list.add(ret.substring(1));%0A            return;%0A        %7D else if (k == s.length()) return;%0A        else if(n == 0) return;%0A        %0A        for(int len=1; len%3C=3 && k+len%3C=s.length(); len++) %7B%0A            String ss = s.substring(k, k+len);%0A            int num = Integer.parseInt(ss);%0A            if((%22%22+num).length() != len) continue;%0A            if(num %3E=0 && num%3C=255) %7B%0A                backtrack(s, k+len, n-1, ret + %22.%22 + num);%0A            %7D%0A        %7D%0A    %7D%0A%7D%0A

Create Restore_IP_Addresses.java