from 2022-09-26 to 2022-10-02

LeetCode

435 无重叠区间

public int eraseOverlapIntervals(int[][] intervals) {

            if(intervals.length == 0) {
                return 0;
            }

            int removeCount = 0;

            Arrays.sort(intervals, Comparator.comparingInt(o -> o[1]));
            int right = intervals[0][1];

            for(int i = 1; i < intervals.length; i++) {
                if(right > intervals[i][0]) {
                    removeCount++;
                } else {
                    right = intervals[i][1];
                }
            }
            return removeCount;
        }
    }

452 用最少数量的箭引爆气球

class Solution {
    public int findMinArrowShots(int[][] points) {
        if(points == null || points.length == 0) {
            return 0;
        }

        Arrays.sort(points, Comparator.comparingInt(arr -> arr[1]));

        int right = points[0][1];
        int removeCount = 0;
        for (int i = 1; i < points.length; i++) {
         
            if(right >= points[i][0]) {
                removeCount++;
            } else {
                right = points[i][1];
            }
        }
        return points.length - removeCount;
    }
  
}

Reading

1. 掘金小册《Netty 入门与实战：仿写微信 IM 即时通讯系统》第 4 节到第 13 节

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