leetcode 435. 无重叠区间

class Solution {
    public int eraseOverlapIntervals(int[][] intervals) {
        Arrays.sort(intervals,(a,b)->a[1]-b[1]);
        int n=intervals.length;
        int right=intervals[0][1];
        int num=1;
        for(int i=1;i<n;i++){
            if(intervals[i][0]>=right){
                right=intervals[i][1];
                num++;
            }
        }
        return n-num;
    }
}