[Leetcode] Problem 1124 - Longest Well-Performing Interval

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We are given hours, a list of the number of hours worked per day for a given employee.

A day is considered to be a tiring day if and only if the number of hours worked is (strictly) greater than 8.

A well-performing interval is an interval of days for which the number of tiring days is strictly larger than the number of non-tiring days.

Return the length of the longest well-performing interval.

Example

Input: hours = [9,9,6,0,6,6,9]

Output: 3

Explanation: The longest well-performing interval is [9,9,6].

Constraints

  • 1 <= hours.length <= 10000
  • 0 <= hours[i] <= 16

Code

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public int longestWPI(int[] hours) {
    int max = 0;
    int sum = 0;
    Map<Integer, Integer> index = new HashMap<>();

    for (int i = 0; i < hours.length; i++) {
        sum += hours[i] > 8 ? 1 : -1;

        if (sum > 0)
            max = i + 1;
        else {
            index.putIfAbsent(sum, i);
            
            if (index.containsKey(sum - 1))
                max = Math.max(max, i - index.get(sum - 1));
        }
    }

    return max;
}