九度 1463 招聘会

#include <iostream>
#include <stdio.h>
#include <vector>
#include <algorithm>
using namespace std;

class Meeting {
public:
    int st, ed;

    Meeting(int _st, int _ed):st(_st), ed(_ed) {
    }

    Meeting() {
        Meeting(0, 0);
    }
    bool operator<(const Meeting &ths) const{
        if(this->ed != ths.ed)
            return this->ed < ths.ed;
        return this->st < ths.st;
    }
};

int main() {
    int n;
    while(scanf("%d", &n) != EOF) {
        vector<Meeting> meetings;
        for(int i = 0; i < n; i ++) {
            int st, ed;
            scanf("%d%d", &st, &ed);
            meetings.push_back(Meeting(st, ed));
        }

        sort(meetings.begin(), meetings.end());

        int res = 0;
        int lastpos = 0;
        for(int i = 0; i < meetings.size(); i ++) {
            if(meetings[i].st >= lastpos) {
                res ++;
                lastpos = meetings[i].ed;
            }
        }
        printf("%d\n", res);
    }

    return 0;
}