【LeetCode】第235场

链接
1.截断句子
直接遍历统计空格数量

class Solution {
public:
    string truncateSentence(string s, int k) {
        int cnt = 0;
        string res = "";
        for(int i = 0;i < s.size(); i++){
            if(s[i] == ' ') cnt++;
            if(cnt == k) break;
            res += s[i];
        }
        return res;
    }
};

或用python一行搞定

class Solution:
    def truncateSentence(self, s: str, k: int) -> str:
        return ' '.join((s.split())[:k])

2.查找用户活跃分钟数

class Solution {
public:
    vector<int> findingUsersActiveMinutes(vector<vector<int>>& logs, int k) {
        unordered_map<int,unordered_set<int>> m;
        for(auto &log : logs){
            m[log[0]].insert(log[1]);
        }
        vector<int> res(k);
        for(auto &i : m){
            res[i.second.size()-1]++;
        }
        return res;
    }
};