2071. Maximum Number of Tasks You Can Assign

import java.util.*;

class Solution {
    public int maxTaskAssign(int[] tasks, int[] workers, int pills, int strength) {
        int ans = 0;
        int l = 0;
        int r = Math.min(tasks.length, workers.length);

        Arrays.sort(tasks);
        Arrays.sort(workers);

        while (l <= r) {
            final int m = (l + r) / 2;
            if (canComplete(tasks, workers, pills, strength, m)) {
                ans = m;
                l = m + 1;

            } else {
                r = m - 1;
            }
        }

        return ans;
    }

    // Returns true if we can finish k tasks.
    private boolean canComplete(int[] tasks, int[] workers, int pillsLeft, int strength, int k) {
        // k strongest workers
        TreeMap<Integer, Integer> sortedWorkers = new TreeMap<>();
        for (int i = workers.length - k; i < workers.length; ++i)
            sortedWorkers.merge(workers[i], 1, Integer::sum);

        // Out of the k smallest tasks, start from the biggest one.
        for (int i = k - 1; i >= 0; --i) {
            // Find the first worker that has strength >= tasks[i].
            Integer lo = sortedWorkers.ceilingKey(tasks[i]);
            if (lo != null) {
                sortedWorkers.merge(lo, -1, Integer::sum);
                if (sortedWorkers.get(lo) == 0) {
                    sortedWorkers.remove(lo);
                }
            } else if (pillsLeft > 0) {
                // Find the first worker that has strength >= tasks[i] - strength.
                lo = sortedWorkers.ceilingKey(tasks[i] - strength);
                if (lo != null) {
                    sortedWorkers.merge(lo, -1, Integer::sum);
                    if (sortedWorkers.get(lo) == 0) {
                        sortedWorkers.remove(lo);
                    }
                    --pillsLeft;
                } else {
                    return false;
                }
            } else {
                return false;
            }
        }

        return true;
    }
}