683. K Empty Slots

class Solution {
    public int kEmptySlots(int[] flowers, int k) {
        int n = flowers.length, inf = Integer.MAX_VALUE, re = inf;
        int[] days = new int[n];
        for(int i = 0; i < n; i++) days[flowers[i] - 1] = i + 1;
        int L = 0, R = L + k + 1;
        for(int i = 0; i < n; i++)
        {
            if(R >= n) break;
            if(i == R) re = Math.min(re, Math.max(days[L], days[R]));
            if(days[i] < days[L] || days[i] < days[R])
            {
                L = i;
                R = L + k + 1;
            }
        }
        return re == inf ? -1 : re;
    }

    public int kEmptySlots1(int[] flowers, int k) {
        int n = flowers.length;
        TreeSet<Integer> set = new TreeSet<>();
        for(int i = 0; i < n; i++)
        {
            int d = flowers[i];
            Integer ceil = set.ceiling(d), floor = set.floor(d);
            if(ceil != null && ceil - d - 1 == k) return i + 1;
            if(floor != null && d - floor - 1 == k) return i + 1;
            set.add(d);
        }
        return -1;
    }
}