[剑指offer 编程题] 字符串的排列

class Solution {
public:
    vector<string> Permutation(string str) {
        if(str.length() == 0)return this->result;      
        int choose_table[9] = {0}; 
        create_string(str,"",0,choose_table);        
        return this->result;       
    }

    void create_string(string str, string c_str,int length,int* choose_table){
        if(length == str.length()){
            //相同的要删除
            if(find(result.begin(),result.end(),c_str) == result.end()) result.push_back(c_str);
        }

        for(int i = 0;i<str.length();i++){
            if(choose_table[i] != -1){
                //回溯
                c_str.push_back(str[i]);
                choose_table[i] = -1;
                create_string(str,c_str,length+1,choose_table);
                choose_table[i] = 0;
                c_str.pop_back();                
            }
        }
    }

private:
    vector<string> result;
};