NumberOfTasksRunning

NumberOfTasksRunning.java

public int[] numberOfTasks(int[] start, int[] end, int[] queries){
        if(start == null || end == null || queries == null){
            throw new IllegalArgumentException("input cannot be null!");
        }
        if(start.length != end.length){
            throw new IllegalArgumentException("Length of start and end must be identical!");
        }
        Arrays.sort(start);
        Arrays.sort(end);
        int[] sortedQueries = Arrays.copyOf(queries, queries.length);
        Arrays.sort(sortedQueries);
        Map<Integer, Integer> resultMapping = new HashMap<>();
        int[] result = new int[queries.length];
        int startIndex = 0;
        int endIndex = 0;
        for (int sortedQuery : sortedQueries) {
            for (; startIndex < start.length; startIndex++) {
                if (start[startIndex] > sortedQuery) {
                    break;
                }
            }
            for (; endIndex < end.length; endIndex++) {
                if (end[endIndex] > sortedQuery) {
                    break;
                }
            }
            resultMapping.put(sortedQuery, startIndex - endIndex);
        }
        for(int i = 0; i < queries.length; i++){
            result[i] = resultMapping.get(queries[i]);
        }
        return result;
    }