Non-overlapping Intervals

Given a collection of intervals, find the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.

Example 1:

Input: [[1,2],[2,3],[3,4],[1,3]]
Output: 1
Explanation: [1,3] can be removed and the rest of intervals are non-overlapping.

Example 2:

Input: [[1,2],[1,2],[1,2]]
Output: 2
Explanation: You need to remove two [1,2] to make the rest of intervals non-overlapping.

Example 3:

Input: [[1,2],[2,3]]
Output: 0
Explanation: You don't need to remove any of the intervals since they're already non-overlapping.

Note:

1. You may assume the interval's end point is always bigger than its start point.

2. Intervals like [1,2] and [2,3] have borders "touching" but they don't overlap each other.

class Solution {
    public int eraseOverlapIntervals(int[][] intervals) {
        if (intervals.length == 0)
            return 0;

        Arrays.sort(intervals, (a, b) -> a[1] - b[1]);
        int end = intervals[0][1];
        int count = 1;
        // Count total number of non overlapping intervals
        for (int i = 1; i < intervals.length; i++) {
            if (intervals[i][0] >= end) {
                end = intervals[i][1];
                count++;
            }
        }
        return intervals.length - count;
    }
}