[Leetcode] Restore IP Addresses

Given a string containing only digits, restore it is returning all possible valid IP address combinations.

For example:
Given "25525511135" ,

Return ["255.255.11.135", "255.255.111.35"] . (Order does not matter)

Hide TagsBacktracking String

Idea: Dfs,backtrace,ip can only be composed of 3 digits, 1, 2, 3 each attempt, 2 bit when the first bit can not be 0, 3 bits is 0~255

classSolution {Vector<string>M_res; Vector<string>m_str;  Public:        voidDfsintDepstrings) {//Printvector (m_str);            if(M_str.size () >4)                return; if(m_str.size () = =4&& DEP <s.size ())return; if(DEP = =s.size ()) {                if(m_str.size () = =4)                {                    stringTmpstr;  for(inti =0; I <3; i++) {Tmpstr+ = (M_str[i] +"."); } tmpstr+ = m_str[3];                M_res.push_back (TMPSTR); }                return; }             for(inti =1; I <=3; i++)            {                if((dep+i-1) >=s.size ()) Break; if(i = =2)                {                    if(S[DEP] = ='0')                         Break; }                Else if(i = =3)                {                    if(S[DEP] = ='1'||(S[DEP]=='2'&& (s[dep+1] <='4'|| (s[dep+1] =='5'&& s[dep+2] <'6'))))                        ; Else                         Break;                } m_str.push_back (S.substr (DEP, i)); DFS (DEP+I, s);            M_str.pop_back (); }} vector<string> restoreipaddresses (strings) {m_res.clear ();            M_str.clear (); DFS (0, s); returnM_res; }};

[Leetcode] Restore IP Addresses