Solution.java

class Solution {
    public int[] countServers(int n, int[][] logs, int x, int[] queries) {
        Arrays.sort(logs, (a, b) -> a[1] - b[1]);
        int m = queries.length;
        int[][] qs = new int[m][0];
        for (int i = 0; i < m; ++i) {
            qs[i] = new int[] {queries[i], i};
        }
        Arrays.sort(qs, (a, b) -> a[0] - b[0]);
        Map<Integer, Integer> cnt = new HashMap<>();
        int[] ans = new int[m];
        int j = 0, k = 0;
        for (var q : qs) {
            int r = q[0], i = q[1];
            int l = r - x;
            while (k < logs.length && logs[k][1] <= r) {
                cnt.merge(logs[k++][0], 1, Integer::sum);
            }
            while (j < logs.length && logs[j][1] < l) {
                if (cnt.merge(logs[j][0], -1, Integer::sum) == 0) {
                    cnt.remove(logs[j][0]);
                }
                j++;
            }
            ans[i] = n - cnt.size();
        }
        return ans;
    }
}