学步园

本题在POJ上貌似无法通过

/*
 * POJ_1328.cpp
 *
 *  Created on: 2013年10月10日
 *      Author: Administrator
 */

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>

using namespace std;

const int maxn = 1010;
int n,d;

struct tt {
	double l, r;
} p[maxn];

void init() {
	int i;
	double x, y,h;
	for (i = 1; i <= n; ++i) {
		scanf("%lf%lf", &x, &y);

		if (y > d) {
			d = -1;
			return;
		}
		h = sqrt(d * d - y * y);
		p[i].l = x - h;
		p[i].r = x + h;
	}
}

bool cmp(tt a, tt b) {
	if (a.r < b.r) {
		return true;
	}

	if ((a.r == b.r) && (a.l < b.l) ) {
		return true;
	}

	return false;
}

void work() {
	int i;

	if (d == -1) {
		printf("-1\n");
		return;
	}
	sort(p + 1, p + 1 + n, cmp);
	int ans = 0;
	double last = -100000000;
	for (i = 1; i <= n; ++i) {
		if (p[i].l <= last) {
			continue;
		}

		ans++;
		last = p[i].r;
	}

	printf("%d\n", ans);
}

int main() {
	int counter = 1;

	while (scanf("%d%d", &n, &d), n || d) {
		printf("Case %d: ",counter++);
		init();
		work();
	}

	return 0;
}