0435 - Non-overlapping Intervals

0435 - Non-overlapping Intervals

Given an array of intervals intervals where intervals[i] = [starti, endi], return the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.

Examples

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

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

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

Constraints

• 1 <= intervals.length <= 105

• intervals[i].length == 2

• -5 * 104 <= starti < endi <= 5 * 104

Java Solution

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

		Arrays.sort(intervals, (a,b) -> (a[0] - b[0]));
        int count = 0;
		int end = intervals[0][1];

		for (int i = 1; i < intervals.length; i++) {
			if(end > intervals[i][0]) {
				end = Math.min(end, intervals[i][1]);
				count++;
			} else {
				end = intervals[i][1];
			}		
        }

		return count;
    }
}