452. 用最少数量的箭引爆气球

class Solution {
    public int findMinArrowShots(int[][] points) {
        int n = points.length;
        if (n == 1) {
            return 1;
        }
        Arrays.sort(points, new Comparator<int[]>() {
            @Override
            public int compare(int[] o1, int[] o2) {
                return Integer.compare(o1[0], o2[0]);
            }
        });
        int result = 0, i = n - 1;
        while (i > -1) {
            int j = i - 1, li = points[i][0];
            while (j > -1 &&  li <= points[j][1]) {
                j--;
            }
            i = j;
            result += 1;
        }
        return result;
    }
}