题目描述

blablabla

样例

blablabla

算法1

Java 代码

import java.io.*;
import java.util.*;

public class Main {

    public static void main(String[] args) throws IOException {
        // 对读入数据进行初始化
        BufferedReader cin = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(cin.readLine());   // 读取一行数据

        // nums[0]存放区间左端点, nums[1]存放区间右端点
        int nums[][] = new int[n][2];
        for (int i = 0; i < n; i++) {
            String[] strs = cin.readLine().split(" ");
            nums[i][0] = Integer.parseInt(strs[0]);
            nums[i][1] = Integer.parseInt(strs[1]);
        }

        int res = merge(nums);

        System.out.println(res);
    }

    private static int merge(int[][] nums){
         Arrays.sort(nums, new Comparator<int[]>() {
            public int compare(int[] o1, int[] o2) {
                return o1[0] - o2[0];
            }
        });

        int res = 0;
        int r = Integer.MIN_VALUE;
        for(int i = 0;i<nums.length;i++){
            if(nums[i][0] > r){
                res++;
            }
            r = Math.max(r, nums[i][1]);
        }
        return res;

    }

}