Leetcode214: Remove Invalid Parentheses

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Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results.

Note: The input string may contain letters other than the parentheses ( and ).

Examples:

"()())()" -> ["()()()", "(())()"]"(a)())()" -> ["(a)()()", "(a())()"]")(" -> [""]

class Solution {public:    void search(string& s, unordered_set<string>& res_set, string& temp, int curr, int open, int s_sz, int& max_valid_len, bool left_deleted){        // dfs        if(s_sz-curr<open) return;        if(curr == s_sz){            if(temp.length()>=max_valid_len && res_set.find(temp) == res_set.end()){                max_valid_len = temp.length();                res_set.insert(temp);            }            return;        }            if(s[curr] != '(' && s[curr] != ')'){            temp += s[curr];            search(s, res_set, temp, curr+1, open, s_sz, max_valid_len, left_deleted);            temp.pop_back();            return;        }        if(s[curr] == '('){            temp += "(";            search(s, res_set, temp, curr+1, open+1, s_sz, max_valid_len, left_deleted);            temp.pop_back();            search(s, res_set, temp, curr+1, open, s_sz, max_valid_len, true);        }        else{            if(!(s[curr] == ')' && open==0)){                temp += ')';                search(s, res_set, temp, curr+1, open-1, s_sz, max_valid_len, left_deleted);                temp.pop_back();            }            if(!left_deleted){                search(s, res_set, temp, curr+1, open, s_sz, max_valid_len, left_deleted);            }        }    }    vector<string> removeInvalidParentheses(string s) {        vector<string> res;        int sz = s.length();        unordered_set<string> res_set;        string temp = "";        int max_valid_len = 0;        search(s, res_set, temp, 0, 0, sz, max_valid_len, false);        for(string a:res_set) res.push_back(a);        return res;    }};

有待思考。。。。。。

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