public int removeCoveredIntervals(int[][] intervals) {
Arrays.sort(intervals, (a, b) -> {
if (a[0] == b[0]) return b[1] - a[1];
return a[0] - b[0];
});
int prevEnd = 0, curEnd = 0;
int res = 0;
for (int[] t : intervals) {
curEnd = t[1];
if (curEnd > prevEnd) {
res++;
prevEnd = curEnd;
}
}
return res;
}