OJ-Problems-Source/HDOJ/3511_autoAC.cpp
2016-09-04 14:11:53 +08:00

112 lines
2.5 KiB
C++

#include <set>
#include <queue>
#include <stack>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <limits.h>
#include <string.h>
#include <string>
#include <algorithm>
#define MID(x,y) ( ( x + y ) >> 1 )
#define L(x) ( x << 1 )
#define R(x) ( x << 1 | 1 )
#define BUG puts("here!!!")
using namespace std;
const int MAX = 100010;
int X;
struct circle{ int w,x,y,r;};
circle c[MAX];
double yy(int id,int flag)
{
double d = sqrt(c[id].r*1.0*c[id].r - (X-c[id].x)*1.0*(X-c[id].x));
if( flag == 1 ) return c[id].y + d;
return c[id].y - d;
}
struct Sline{
int flag,id;
bool operator<(const Sline a)const
{
double y1 = yy(id, flag);
double y2 = yy(a.id, a.flag);
return y1 > y2 || y1 == y2 && flag > a.flag;
}
};
set<Sline> s;
set<Sline>::iterator pre,suc,it;
struct event{ int x,id,flag;};
event l[MAX];
bool cmp(event a,event b)
{
if( a.x == b.x )
return c[a.id].y > c[b.id].y;
return a.x < b.x;
}
void add_line(circle c, int &cnt ,int id)
{
l[cnt].id = id;
l[cnt].x = c.x - c.r;
l[cnt++].flag = 1;
l[cnt].id = id;
l[cnt].x = c.x + c.r;
l[cnt++].flag = -1;
}
void solve(int n)
{
s.clear();
Sline node;
for(int i=0; i<n; i++)
{
X = l[i].x;
if( l[i].flag == 1 )
{
node.id = l[i].id; node.flag = 1;
it = s.insert(node).first;
suc = pre = it;
suc++;
if( it == s.begin() || suc == s.end() )
c[it->id].w = 1;
else
{
pre--;
if( pre->id == suc->id )
c[it->id].w = c[pre->id].w + 1;
else
c[it->id].w = max( c[pre->id].w, c[suc->id].w);
}
node.flag = -1;
s.insert(node);
}
else
{
node.id = l[i].id; node.flag = 1;
s.erase(node);
node.flag = -1;
s.erase(node);
}
}
}
int main()
{
int ncases,n;
int x1,x2,y1,y2,xx,yy,r;
while( ~scanf("%d",&n) )
{
int cnt = 0;
for(int i=0; i<n; i++)
{
scanf("%d%d%d",&c[i].x, &c[i].y, &c[i].r);
c[i].w = 0;
add_line(c[i],cnt,i);
}
sort(l,l+cnt,cmp);
solve(cnt);
int ans = 0;
for(int i=0; i<n; i++)
ans = max(ans, c[i].w);
printf("%d\n",ans);
}
return 0;
}