【最长下降子序列+nlog(n)】北大 POJ 1548 Robots

/* THE PROGRAM IS MADE BY PYY */
/*----------------------------------------------------------------------------//
    Copyright (c) 2012 panyanyany All rights reserved.

    URL   : http://poj.org/problem?id=1548
    Name  : 1548 Robots

    Date  : Monday, July 9, 2012
    Time Stage : half an hour

    Result:
10405836	panyanyany
1548
Accepted	172K	0MS	C++
1775B	2012-07-09 13:02:39

Test Data :

Review :

//----------------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <vector>

#include <algorithm>
#include <iostream>
#include <queue>
#include <set>
#include <string>

using namespace std ;

#define MEM(a, v)        memset (a, v, sizeof (a))    // a for address, v for value
#define max(x, y)        ((x) > (y) ? (x) : (y))
#define min(x, y)        ((x) < (y) ? (x) : (y))

#define INF     (0x3f3f3f3f)
#define MAXN	(24*25)

#define L(x)	((x)<<1)
#define R(x)	(((x)<<1)|1)
#define M(x, y)	(((x)+(y)) >> 1)

#define DB    //

struct NODE {
	int x, y;
};

bool cmp(const NODE &lhs, const NODE &rhs)
{
	if (lhs.x == rhs.x)
		return lhs.y < rhs.y;
	return lhs.x < rhs.x;
}

NODE a[MAXN];
int order[MAXN];

int LDesS(NODE a[], int n)
{
	int i, r, l, len, m;
	MEM(order, 0);
	sort(a, a+n, cmp);
	len = 1;
	for (i = 0; i < n; ++i)
	{
		l = 1;
		r = len;
		while (l <= r)
		{
			m = (l + r) >> 1;
			if (order[m] > a[i].y)
				l = m + 1;
			else
				r = m - 1;
		}

		if (order[l] < a[i].y)
			order[l] = a[i].y;
		len = max(len, l);
	}
	return len;
}

int main()
{
	int x, y, n;
	n = 0;
	while (scanf("%d %d", &x, &y) != EOF)
	{
		if (x == -1 && y == -1)
			break;

		if (x != 0 && y != 0)
		{
			a[n].x = x;
			a[n].y = y;
			++n;
		}
		else
		{
			printf("%d\n", LDesS(a, n));
			n = 0;
		}
	}
	return 0;
}