不重叠区间最多的数量 Java

[1,2],[2,3],[3,4],[1,3]] 中最多有3个不重叠区间

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