安排会议(区间问题、贪心)

import java.io.BufferedInputStream;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class test {

    public static class Program {
        int start, end;

        public Program(int start, int end) {
            this.start = start;
            this.end = end;
        }
    }

    public static int bestArrange(Program[] p) {
        int ans = 0;
        Arrays.sort(p, new Comparator<Program>() { // 哪场会议结束时间早就排在前面
            public int compare(Program o1, Program o2) {
                return o1.end - o2.end;
            }
        });
        int start = 0;
        for (int i = 0; i < p.length; ++i) {
           if (start <= p[i].start) {  // 端点不重合可以去掉等号
               start = p[i].end; // 记录下一场能开始的时间
               ++ans;
           }
        }
        return ans;
    }

    public static void main(String[] args) {
        Scanner cin = new Scanner(new BufferedInputStream(System.in));
        int n = cin.nextInt();
        Program[] p = new Program[n];
        for (int i = 0; i < n; ++i) {
            int start = cin.nextInt();
            int end = cin.nextInt();
            p[i] = new Program(start, end);
        }
        cin.close();
        System.out.println(bestArrange(p));
    }
}