洛谷 [P2859] 摊位预定

贪心

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std;
const int MAXN = 50005;
int init() {
	int rv = 0, fh = 1;
	char c = getchar();
	while(c < '0' || c > '9') {
		if(c == '-') fh = -1;
		c = getchar();
	}
	while(c >= '0' && c <= '9') {
		rv = (rv<<1) + (rv<<3) + c - '0';
		c = getchar();
	}
	return fh * rv;
}
struct cow{
	int s, t, num;
	bool operator < (const cow & b) const {
		return s < b.s;
	}
}a[MAXN];
struct ket{
	int num, tim;
	bool operator < (const ket & b) const {
		return tim > b.tim;
	}
};
int n, ans[MAXN], cnt;
priority_queue <ket> q;
int main() {
	n = init();
	for(int i = 1; i <= n; i++) {
		cin >> a[i].s >> a[i].t;
		a[i].num = i;
	}
	sort(a + 1, a + n + 1);
	q.push({1, a[1].t});
	ans[a[1].num] = 1;
	cnt++;
	for(int i = 2; i <= n; i++) {
		if(q.top().tim < a[i].s) {
			ket t;
			t = q.top();
			q.pop();
			t.tim = a[i].t;
			q.push(t);
			ans[a[i].num] = t.num;
		}else {
			cnt++;
			ket t;
			t.num = cnt;
			t.tim = a[i].t;
			q.push(t);
			ans[a[i].num] = cnt;
		}
	}
	cout << cnt << endl;
	for(int i = 1;i <= n; i++) {
		printf("%d\n", ans[i]);
	}
	return 0;
}