1124. Longest Well-Performing Interval

Problem

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 1:

Input: hours = [9,9,6,0,6,6,9]
Output: 3
Explanation: The longest well-performing interval is [9,9,6].

Example 2:

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

  Constraints:

• 1 <= hours.length <= 10^4

• 0 <= hours[i] <= 16

Solution (Java)

class Solution {
    public int longestWPI(int[] hours) {
        int i = 0;
        HashMap<Integer, Integer> map = new HashMap<>();
        int sum = 0;
        map.put(sum, -1);
        int max = Integer.MIN_VALUE;
        for (int val : hours) {
            sum += (val > 8) ? 1 : -1;
            if (!map.containsKey(sum)) {
                map.put(sum, i);
            }
            if (sum > 0) {
                max = i + 1;
            } else if (map.containsKey(sum - 1)) {
                max = Math.max(i - map.get(sum - 1), max);
            }
            i++;
        }
        if (max == Integer.MIN_VALUE) {
            max = 0;
        }
        return max;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).