140 lines
4.8 KiB
C++
140 lines
4.8 KiB
C++
#include<cstdio>
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#include<cstdlib>
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#include<cstring>
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#include<cmath>
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#include<map>
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#include<algorithm>
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using namespace std;
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typedef long long ll;
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const int maxn = 105;
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const int forever = -1;
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const int never = -2;
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struct point
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{
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ll x, y;
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} p[maxn], v[maxn];
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map <ll, ll> Map;
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ll cti[maxn][maxn];
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void initial(int n)
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{
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int i, j, t;
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for(i=0; i<n; i++)
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for(j=i+1; j<n; j++)
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{
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if(p[i].x==p[j].x && p[i].y==p[j].y && v[i].x==v[j].x && v[i].y==v[j].y)
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cti[i][j]=cti[j][i]=forever;
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else
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{
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cti[i][j]=cti[j][i]=never;
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if(v[i].x != v[j].x)
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{
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if((p[i].x-p[j].x)%(v[j].x-v[i].x) != 0)continue;
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t=(p[i].x-p[j].x)/(v[j].x-v[i].x);
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if(t<0 || (p[i].y+v[i].y*t != p[j].y+v[j].y*t))continue;
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}
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else if(v[i].y != v[j].y)
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{
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if((p[i].y-p[j].y)%(v[j].y-v[i].y) != 0)continue;
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t=(p[i].y-p[j].y)/(v[j].y-v[i].y);
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if(t<0 || (p[i].x+v[i].x*t != p[j].x+v[j].x*t))continue;
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}
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else continue;
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cti[i][j]=cti[j][i]=t;
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}
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}
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}
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int main()
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{
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int i, j, k, n, tmp, cnt, res, ans;
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ll a, b, c, t;
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while(~scanf("%d", &n) && n)
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{
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for(i = 0; i < n; i++)scanf("%I64d%I64d%I64d%I64d", &p[i].x, &p[i].y, &v[i].x, &v[i].y);
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if(n == 1 || n == 2)
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{
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printf("%d\n", n);
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continue;
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}
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initial(n);
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ans = 0;
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for(i = 0; i < n; i++)
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for(j = i+1; j < n; j++)
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{
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Map.clear();
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cnt = 0;
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res = 0;
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for(k = 0; k < n; k++)
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{
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if(k==i || k==j)continue;
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a = (v[i].x-v[j].x)*(v[i].y-v[k].y) - (v[i].x-v[k].x)*(v[i].y-v[j].y);
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b = (p[i].x-p[j].x)*(v[i].y-v[k].y) + (v[i].x-v[j].x)*(p[i].y-p[k].y)
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- (p[i].y-p[j].y)*(v[i].x-v[k].x) - (v[i].y-v[j].y)*(p[i].x-p[k].x);
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c = (p[i].x-p[j].x)*(p[i].y-p[k].y) - (p[i].y-p[j].y)*(p[i].x-p[k].x);
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if(a==0 && b==0 && c==0)cnt++;
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else if(a==0)
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{
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if(c==0 || b==0)continue;
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else if(c%b==0)
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{
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t=-c/b;
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if(t>0 && t!=cti[i][j])
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{
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tmp = ++Map[t];
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res = max(tmp, res);
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}
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}
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}
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else
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{
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ll d = b*b-4*a*c;
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ll t1, t2;
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if(d<0) continue;
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else
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{
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ll sqd = sqrt(d+0.0);
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if(sqd*sqd == d)
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{
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t1= -b+sqd;
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if(t1%(2*a)==0)
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{
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t1/=(2*a);
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if(t1>0 && t1!=cti[i][j])
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{
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tmp = ++Map[t1];
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res = max(tmp, res);
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}
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}
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if(sqd!=0)
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{
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t2= -b-sqd;
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if(t2%(2*a)==0)
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{
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t2/=(2*a);
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if(t2>0 && t2!=cti[i][j])
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{
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tmp = ++Map[t2];
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res = max(tmp, res);
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}
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}
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}
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}
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}
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}
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}
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ans = max(res+2+cnt, ans);
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if(cti[i][j]!=never && cti[i][j]!=0)
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{
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res=0;
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for(k=0; k<n; k++)
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{
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if(k==i || k==j)continue;
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if(cti[i][j] == cti[i][k])res++;
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}
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ans=max(res+2, ans);
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}
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}
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printf("%d\n", ans);
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}
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return 0;
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}
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