День 8 — Хранение ключей и значений на основе времени

https://leetcode.com/problems/time-based-key-value-store/

class TimeMap {
    Map<String, List<String>> keyVal;
    Map<String, List<Integer>> timeSeriesMap;
    public TimeMap() {
        keyVal = new HashMap<>();
        timeSeriesMap = new HashMap<>();
    }
    
    public void set(String key, String value, int timestamp) {
        List<String> lsVal;
        List<Integer> lsTime;
        if(timeSeriesMap.containsKey(key)){
            lsTime = timeSeriesMap.get(key);
            lsTime.add(timestamp);
            lsVal = keyVal.get(key);
            lsVal.add(value);
        } else {
            lsTime = new ArrayList<>();
            lsTime.add(timestamp);
            lsVal =  new ArrayList<>();
            lsVal.add(value);
        }
        keyVal.put(key, lsVal);
        timeSeriesMap.put(key, lsTime);
    }
    
    public String get(String key, int timestamp) {
        if(timeSeriesMap.containsKey(key)){
            int index = getIndexForTimeStamp(timeSeriesMap.get(key), timestamp);
            if( index == -1) return "";
            return keyVal.get(key).get(index);
        } else {
            return "";
        } 
    }
    
    private int getIndexForTimeStamp(List<Integer> lsTime, int timestamp) {
        
        int s = 0 , e = lsTime.size() - 1;
        if ( timestamp < lsTime.get(0) ) return -1;
        if ( timestamp >= lsTime.get(e) ) return e;
        
        while ( s < e-1 ) {
            int mid = s + (e - s) / 2 ;
            if (lsTime.get(mid) == timestamp) return mid;
            if (lsTime.get(mid) > timestamp) e = mid - 1;
            if (lsTime.get(mid) < timestamp) s = mid;           
        }
        return s;
    }
}
/**
 * Your TimeMap object will be instantiated and called as such:
 * TimeMap obj = new TimeMap();
 * obj.set(key,value,timestamp);
 * String param_2 = obj.get(key,timestamp);
 */