OJ-Problems-Source/HDOJ/4082_autoAC.cpp

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#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
using namespace std;
const int MAXN = 20;
const int MAXM = 820;
int ans, n, d[MAXN][MAXN], m, ns;
int used[210][210];
struct point
{
int x, y;
}p[MAXN];
struct triangle
{
int a, b, c;
}t[MAXM];
int dist(point p1, point p2)
{
int x, y;
x = p1.x - p2.x;
y = p1.y - p2.y;
return x * x + y * y;
}
bool ponls(point p0, point p1, point p2)
{
int x1, x2, y1, y2;
x1 = p0.x - p2.x;
y1 = p0.y - p2.y;
x2 = p1.x - p2.x;
y2 = p1.y - p2.y;
if(x1 * y2 == x2 * y1)
return true;
return false;
}
bool similar(triangle t1, triangle t2)
{
int a1, a2, b1, b2, c1, c2;
a1 = t1.a, b1 = t1.b, c1 = t1.c;
a2 = t2.a, b2 = t2.b, c2 = t2.c;
if(a1 * b2 == b1 * a2 && a1 * c2 == c1 * a2 && b1 * c2 == c1 * b2)
return true;
return false;
}
void ReadGraph()
{
int i, j, k, s, v;
n = 0;
memset(used, 0, sizeof used);
for(i = 1; i <= ns; i ++)
{
scanf("%d%d", &s, &v);
s += 100, v += 100;
if(used[s][v]) continue;
used[s][v] = 1;
p[++ n].x = s;
p[n]. y = v;
}
for(i = 1; i <= n; i ++)
for(j = 1; j <= n; j ++)
d[i][j] = d[j][i] = dist(p[i], p[j]);
}
void MakeTriangle()
{
int i, j, k, temp[3];
m = 0;
for(i = 1; i <= n; i ++)
for(j = i + 1; j <= n; j ++)
for(k = j + 1; k <= n; k ++)
{
if(ponls(p[i], p[j], p[k]))
continue;
temp[0] = d[i][j];
temp[1] = d[j][k];
temp[2] = d[i][k];
sort(temp, temp + 3);
t[++ m].a = temp[0];
t[m].b = temp[1];
t[m].c = temp[2];
}
}
void cal()
{
int cnt, i, j;
ans = 0;
for(i = 1; i <= m; i ++)
{
cnt = 1;
for(j = i + 1; j <= m; j ++)
{
if( similar(t[i], t[j]))
++ cnt;
}
ans = max(ans, cnt);
}
}
int main()
{
while(scanf("%d", &ns), ns)
{
ReadGraph();
MakeTriangle();
cal();
printf("%d\n", ans);
}
return 0;
}