区间问题

1. 缩

LeetCode：452. 用最少数量的箭引爆气球

class Solution {
    public int findMinArrowShots(int[][] points) {
    	int res = 0;
		List<Point> list = new ArrayList<>();
		for (int[] point : points) {
			list.add(new Point(point[0], point[1]));
		}
		Collections.sort(list, new Comparator<Point>() {
			@Override
			public int compare(Point o1, Point o2) {
				if (o1.left != o2.left){
					return Long.compare(o1.left, o2.left);
				}
				return Long.compare(o1.right, o2.right);
			}
		});

		for (int i = 0; i < list.size(); i++) {
			Point point = list.get(i);
			res++;
			while (i + 1 < list.size() && point.right >= list.get(i + 1).left){  //  尽量去缩进
				point.left = Math.max(point.left, list.get(i + 1).left);
				point.right = Math.min(point.right, list.get(i + 1).right);
				i++;
			}
		}
		return res;
    }
}
class Point{
	long left;
	long right;

	public Point(long left, long right) {
		this.left = left;
		this.right = right;
	}
}