leetcode-hard记录44. Wildcard Matching

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本文介绍了一种基于正则表达式的字符串匹配算法，通过构建状态机和使用队列进行状态转移，实现了对输入字符串的有效匹配。算法在C++中实现，通过案例测试，运行时间和内存使用情况优于大部分提交。

√ Accepted
  √ 1809/1809 cases passed (76 ms)
  √ Your runtime beats 44.13 % of cpp submissions
  √ Your memory usage beats 11.54 % of cpp submissions (24.3 MB)


class Solution {
public:
        bool isMatch(string s, string p) {
        string state = "";
        queue<int> q;
        int flag = 1;
        for (int i = 0; i < p.size(); i++)
        {
            if(p[i] != '*')
            {
                state = state + p[i];
                flag = 1;
            }
            else
            {
                if(flag == 1)
                {
                   state = state + '-' + '+';
                   flag = 0;
                }

            }
        }
        state = state + '.';
        vector<int> v(state.size());
        q.push(0);
        v[0] = 1;
        int temp1 = 0;
        while(state[temp1] == '-')
        {
            q.push(temp1+1);
            v[temp1+1] = 1;
            q.push(temp1+2);
            v[temp1+2] = 1;
            temp1 = temp1 + 2;
        }
        int temp = 0;
        queue<int> qTemp;
        for (int i = 0; i < s.size(); i++)
        {
            temp = q.size();
            
            for (int j = 0; j < temp; j++)
            {
                if(state[q.front()] == s[i] || state[q.front()] == '?' || state[q.front()] == '+')
                {
                    if(state[q.front()] == '+')
                    {
                        temp1 = q.front();
                        q.push(temp1);
                        q.pop();
                    }
                    else
                    {
                        temp1 = q.front()+1;
                        if(state[temp1] == '.' && i == s.size()-1)
                        {
                            return true;
                        }
                        q.push(temp1);
                        v[temp1] = 1;
                        q.pop();
                        v[temp1-1] = 0;
                    }

                    while (temp1 < state.size() && (state[temp1] == '-' || state[temp1] == '+'))
                    {
                        if(state[temp1+1] == '.' && i == s.size()-1 )
                        {
                            return true;
                        }

                        qTemp.push(temp1 + 1);

                        temp1++;
                    }
                }
                else
                {
                    v[q.front()] = 0;
                    q.pop();
                }
            }
            temp = qTemp.size();
            for(int j = 0; j < temp; j++)
            {
                if(v[qTemp.front()] == 0)
                {
                    q.push(qTemp.front());
                    v[qTemp.front()] = 1;
                }
                qTemp.pop();
            }

        }
        temp = q.size();
        for (int j = 0; j < temp; j++)
        {
            if(s.size() == 0 && state[q.front()] == '.')
            {
                return true;
            }
            q.pop();
        }
        return false;

    }
};