[单调队列] BZOJ 1071 [SCOI2007]组队

怎么看都是n3

然后弱弱的去膜了题解：http://www.cnblogs.com/rausen/p/4007292.html

#include<cstdio>
#include<cstdlib>
#include<algorithm>
using namespace std;
typedef long long ll; 

inline char nc()
{
	static char buf[100000],*p1=buf,*p2=buf;
	if (p1==p2) { p2=(p1=buf)+fread(buf,1,100000,stdin); if (p1==p2) return EOF; }
	return *p1++;
}

inline void read(int &x)
{
	char c=nc(),b=1;
	for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;
	for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;
}

inline void read(ll &x)
{
	char c=nc(),b=1;
	for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;
	for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;
}
 
int n,ans;
ll A,B,C,Max,Min;

const int N=5005;

struct abcd{
    ll sum,h,s;
    void calc() { sum=A*h+B*s; }
}x[N],y[N];
 
bool cmph(const abcd &a, const abcd &b){ return a.h<b.h; }
bool cmps(const abcd &a, const abcd &b){ return a.sum<b.sum; }
 
inline bool check(abcd x){ return x.s<=Max && x.s>=Min; }
 
int main()
{
	freopen("t.in","r",stdin);
	freopen("t.out","w",stdout);
	int l,r,cnt;
	read(n); read(A); read(B); read(C);
	for (int i=1;i<=n;i++)
		read(x[i].h),read(x[i].s),x[i].calc(),y[i]=x[i];	 
	sort(x+1,x+n+1,cmph);
	sort(y+1,y+n+1,cmps);
	for (int i=1;i<=n;i++)
	{
		Min=x[i].s,Max=Min+C/B;
		l=r=cnt=0;
		for (int j=1;j<=n;j++)
		{
			while (r<n && y[r+1].sum<=A*x[j].h+B*x[i].s+C)
				cnt+=check(y[++r]);
			while (l<n && x[l+1].h<x[j].h)
				cnt-=check(x[++l]);
			ans=max(ans,cnt);	
		}
	}
	printf("%d\n",ans);
	return 0;
}