435. Non-overlapping Intervals

class Solution:
    def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int:
        end = float('-inf')
        count = 0
        
        # sort by end time
        sorted_intervals = sorted(intervals, key=lambda x: x[1])
        
        for interval in sorted_intervals:
            # check if interval is not overlapping and shift window
            if interval[0] >= end:
                end = interval[1]
            else:
                count += 1
                
        return count