2747. 统计没有收到请求的服务器数目

题意

题目链接

思路

代码

class Solution {
public:
    vector<int> countServers(int n, vector<vector<int>>& logs, int x, vector<int>& queries) {
        sort(logs.begin(), logs.end(), [](vector<int> &a, vector<int>&b){return a[1] < b[1];});

        vector<pair<int, int>> vec;
        for (int i = 0; i < queries.size(); ++i)
            vec.push_back(make_pair(queries[i], i));
        sort(vec.begin(), vec.end());
        unordered_map<int, int> mp;
        vector<int> ans(queries.size());

        int l = 0, r = 0;
        for (auto &index:vec) {
            while (r < logs.size() && logs[r][1] <= index.first)
                mp[logs[r++][0]]++;
            while (l < logs.size() && logs[l][1] < index.first - x){
                int &x = mp[logs[l][0]];
                x--;
                if (x == 0)
                    mp.erase(logs[l][0]);
                l++;
            }
            ans[index.second] = n - mp.size();
        }
        return ans;
    }
};