You are given a positive integer days representing the total number of days an employee is available for work (starting from day 1). You are also given a 2D array meetings of size n where, meetings[i] = [start_i, end_i] represents the starting and ending days of meeting i (inclusive).
Return the count of days when the employee is available for work but no meetings are scheduled.
Note: The meetings may overlap.
Example 1:
Input: days = 10, meetings = [[5,7],[1,3],[9,10]]
Output: 2
Explanation:
There is no meeting scheduled on the 4th and 8th days.
Example 2:
Input: days = 5, meetings = [[2,4],[1,3]]
Output: 1
Explanation:
There is no meeting scheduled on the 5th day.
Example 3:
Input: days = 6, meetings = [[1,6]]
Output: 0
Explanation:
Meetings are scheduled for all working days.
Constraints:
1 <= days <= 1091 <= meetings.length <= 105meetings[i].length == 21 <= meetings[i][0] <= meetings[i][1] <= daysclass Solution {
public int countDays(int days, int[][] meetings) {
TreeMap<Integer, Integer> calendar = new TreeMap<>();
for (int[] m : meetings) {
calendar.put(m[0], calendar.getOrDefault(m[0], 0) + 1);
calendar.put(m[1] + 1, calendar.getOrDefault(m[1] + 1, 0) - 1);
}
int concurrentMeets = 0, prevDay = calendar.firstKey(), freeDays = calendar.firstKey();
for (Map.Entry<Integer, Integer> e : calendar.entrySet()) {
if (concurrentMeets == 0) {
freeDays += e.getKey() - prevDay;
}
concurrentMeets += e.getValue();
prevDay = e.getKey();
}
return freeDays + days - prevDay;
}
}class Solution {
public int countDays(int days, int[][] meetings) {
TreeMap<Integer, Integer> calendar = new TreeMap<>();
for (int[] m : meetings) {
calendar.put(m[0], calendar.getOrDefault(m[0], 0) + 1);
calendar.put(m[1] + 1, calendar.getOrDefault(m[1] + 1, 0) - 1);
}
int concurrentMeets = 0, prevDay = calendar.firstKey(), freeDays = calendar.firstKey();
for (Map.Entry<Integer, Integer> e : calendar.entrySet()) {
if (concurrentMeets == 0) {
freeDays += e.getKey() - prevDay;
}
concurrentMeets += e.getValue();
prevDay = e.getKey();
}
return freeDays + days - prevDay;
}
}