题解 | #设计LRU缓存结构#

C++利用队列和vector数组实现，其中队列记录新旧顺序

class Solution {
public:
    /**
     * lru design
     * @param operators int整型vector<vector<>> the ops
     * @param k int整型 the k
     * @return int整型vector
     */
    vector<int> LRU(vector<vector<int> >& operators, int k) {
        // write code here
        vector<vector<int>> n(k,vector<int>(2,0));
        queue<int> a;
        vector<int> p;
        for (int i=0;i<operators.size();++i)
        {
            if (operators[i][0]==1)
            {
                if(a.size()<k)
                {
                    n[a.size()][0]=operators[i][1];
                    n[a.size()][1]=operators[i][2];
                    a.push(a.size());
                }
                else
                {
                    int c=a.front();
                    a.pop();
                    a.push(c);
                    n[c][0]=operators[i][1];
                    n[c][1]=operators[i][2];
                }
            }
            else
            {
                int c2=-1;
                for (int j=0;j<a.size();++j)
                {
                    if (n[j][0]==operators[i][1])
                    {
                        c2=n[j][1];
                        queue<int> b;
                        while(a.size())
                        {
                            if(a.front()==j);
                            else
                                b.push(a.front());
                             a.pop();
                        }
                        b.push(j);
                        a=b;
                        break;
                    }
                }
                p.push_back(c2);
            }
        }
        return p;
    }
};