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1604. Alert Using Same Key-Card Three or More Times in a One Hour Period

Description

LeetCode company workers use key-cards to unlock office doors. Each time a worker uses their key-card, the security system saves the worker's name and the time when it was used. The system emits an alert if any worker uses the key-card three or more times in a one-hour period.

You are given a list of strings keyName and keyTime where [keyName[i], keyTime[i]] corresponds to a person's name and the time when their key-card was used in a single day.

Access times are given in the 24-hour time format "HH:MM", such as "23:51" and "09:49".

Return a list of unique worker names who received an alert for frequent keycard use. Sort the names in ascending order alphabetically.

Notice that "10:00" - "11:00" is considered to be within a one-hour period, while "22:51" - "23:52" is not considered to be within a one-hour period.

 

Example 1:

Input: keyName = ["daniel","daniel","daniel","luis","luis","luis","luis"], keyTime = ["10:00","10:40","11:00","09:00","11:00","13:00","15:00"]
Output: ["daniel"]
Explanation: "daniel" used the keycard 3 times in a one-hour period ("10:00","10:40", "11:00").

Example 2:

Input: keyName = ["alice","alice","alice","bob","bob","bob","bob"], keyTime = ["12:01","12:00","18:00","21:00","21:20","21:30","23:00"]
Output: ["bob"]
Explanation: "bob" used the keycard 3 times in a one-hour period ("21:00","21:20", "21:30").

 

Constraints:

  • 1 <= keyName.length, keyTime.length <= 105
  • keyName.length == keyTime.length
  • keyTime[i] is in the format "HH:MM".
  • [keyName[i], keyTime[i]] is unique.
  • 1 <= keyName[i].length <= 10
  • keyName[i] contains only lowercase English letters.

Solutions

  • class Solution {
        public List<String> alertNames(String[] keyName, String[] keyTime) {
            Map<String, List<Integer>> d = new HashMap<>();
            for (int i = 0; i < keyName.length; ++i) {
                String name = keyName[i];
                String time = keyTime[i];
                int t
                    = Integer.parseInt(time.substring(0, 2)) * 60 + Integer.parseInt(time.substring(3));
                d.computeIfAbsent(name, k -> new ArrayList<>()).add(t);
            }
            List<String> ans = new ArrayList<>();
            for (var e : d.entrySet()) {
                var ts = e.getValue();
                int n = ts.size();
                if (n > 2) {
                    Collections.sort(ts);
                    for (int i = 0; i < n - 2; ++i) {
                        if (ts.get(i + 2) - ts.get(i) <= 60) {
                            ans.add(e.getKey());
                            break;
                        }
                    }
                }
            }
            Collections.sort(ans);
            return ans;
        }
    }
    
  • class Solution {
    public:
        vector<string> alertNames(vector<string>& keyName, vector<string>& keyTime) {
            unordered_map<string, vector<int>> d;
            for (int i = 0; i < keyName.size(); ++i) {
                auto name = keyName[i];
                auto time = keyTime[i];
                int a, b;
                sscanf(time.c_str(), "%d:%d", &a, &b);
                int t = a * 60 + b;
                d[name].emplace_back(t);
            }
            vector<string> ans;
            for (auto& [name, ts] : d) {
                int n = ts.size();
                if (n > 2) {
                    sort(ts.begin(), ts.end());
                    for (int i = 0; i < n - 2; ++i) {
                        if (ts[i + 2] - ts[i] <= 60) {
                            ans.emplace_back(name);
                            break;
                        }
                    }
                }
            }
            sort(ans.begin(), ans.end());
            return ans;
        }
    };
    
  • class Solution:
        def alertNames(self, keyName: List[str], keyTime: List[str]) -> List[str]:
            d = defaultdict(list)
            for name, t in zip(keyName, keyTime):
                t = int(t[:2]) * 60 + int(t[3:])
                d[name].append(t)
            ans = []
            for name, ts in d.items():
                if (n := len(ts)) > 2:
                    ts.sort()
                    for i in range(n - 2):
                        if ts[i + 2] - ts[i] <= 60:
                            ans.append(name)
                            break
            ans.sort()
            return ans
    
    
  • func alertNames(keyName []string, keyTime []string) (ans []string) {
    	d := map[string][]int{}
    	for i, name := range keyName {
    		var a, b int
    		fmt.Sscanf(keyTime[i], "%d:%d", &a, &b)
    		t := a*60 + b
    		d[name] = append(d[name], t)
    	}
    	for name, ts := range d {
    		n := len(ts)
    		if n > 2 {
    			sort.Ints(ts)
    			for i := 0; i < n-2; i++ {
    				if ts[i+2]-ts[i] <= 60 {
    					ans = append(ans, name)
    					break
    				}
    			}
    		}
    	}
    	sort.Strings(ans)
    	return
    }
    
  • function alertNames(keyName: string[], keyTime: string[]): string[] {
        const d: { [name: string]: number[] } = {};
        for (let i = 0; i < keyName.length; ++i) {
            const name = keyName[i];
            const t = keyTime[i];
            const minutes = +t.slice(0, 2) * 60 + +t.slice(3);
            if (d[name] === undefined) {
                d[name] = [];
            }
            d[name].push(minutes);
        }
        const ans: string[] = [];
        for (const name in d) {
            if (d.hasOwnProperty(name)) {
                const ts = d[name];
                if (ts.length > 2) {
                    ts.sort((a, b) => a - b);
                    for (let i = 0; i < ts.length - 2; ++i) {
                        if (ts[i + 2] - ts[i] <= 60) {
                            ans.push(name);
                            break;
                        }
                    }
                }
            }
        }
        ans.sort();
        return ans;
    }
    
    

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