Codeforces 249D Donkey and Stars (线段树+扫描线)

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <ctime>
#include <cstdlib>
#include <functional>
#pragma comment(linker,"/STACK:102400000,102400000")
using namespace std;


#define eps 1e-10
#define N 300030
#define B 20
#define M 3000020
#define inf 0x3f3f3f3f
#define LL long long
#define pii pair<int, int>
#define MP make_pair
#define fi first
#define se second
#define mod 1000000007
#define ls (i << 1)
#define rs (ls | 1)
#define md (ll + rr >> 1)
#define lson ll, md, ls
#define rson md + 1, rr, rs

int n, a, b, c, d;
LL san[N], cnt;
int dp[N];

struct node {
	int x, y;
	bool operator < (const node &t) const {
		LL u = 1LL * c * x - 1LL * d * y;
		LL v = 1LL * c * t.x - 1LL * d * t.y;
		if(u != v) return u > v;
		return 1LL * a * x - 1LL * b * y > 1LL * a * t.x - 1LL * b * t.y;
	}
}p[N];

int mx[N];

void upd(int x, int v) {
	while(x <= cnt) {
		mx[x] = max(mx[x], v);
		x += x & -x;
	}
}
int query(int x) {
	int ret = 0;
	while(x) {
		ret = max(ret, mx[x]);
		x -= x & -x;
	}
	return ret;
}
int haxi(LL x) {
	return lower_bound(san + 1, san + cnt + 1, x) - san;
}
int main() {
	scanf("%d", &n);
	scanf("%d/%d%d/%d", &a, &b, &c, &d);

	for(int i = 1; i <= n; ++i) {
		scanf("%d%d", &p[i].x, &p[i].y);
		san[++cnt] = 1LL * a * p[i].x - 1LL * b * p[i].y;
	}
	n++; p[n].x = 0, p[n].y = 0;
	san[++cnt] = 0;
	sort(p + 1, p + n + 1);
	sort(san + 1, san + cnt + 1);
	cnt = unique(san + 1, san + cnt + 1) - san - 1;

	for(int i = 1; i <= n; ++i) {
		LL tmp = 1LL * a * p[i].x - 1LL * b * p[i].y;
		int pp = haxi(tmp);
		dp[i] = query(pp - 1) + 1;
		upd(pp, dp[i]);
	}

	for(int i = 1; i <= n; ++i) {
		if(p[i].x == 0 && p[i].y == 0) {
			printf("%d\n", dp[i] - 1);
			break;
		}
	}
	return 0;
}