POJ-1088 滑雪 dp

#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
using namespace std;

int N;

struct Point {
double x, y;
void read() {
scanf("%lf %lf", &x, &y);
}
}p[105];

int main() {
int T, ret, ca = 0;
scanf("%d", &T);
while (T--) {
ret = 0x7fffffff+1;
scanf("%d", &N);
for (int i = 0; i < N; ++i) {
p[i].read();
}
if (N == 1) {
ret = 1;
} else {
for (int i = 0; i < N; ++i) {
for (int j = i+1; j < N; ++j) { // 枚举出所有的直线
int cnt = 2;
double x = p[j].x - p[i].x;
double y = p[j].y - p[i].y;
for (int k = j+1; k < N; ++k) {
double a = p[k].x - p[i].x;
double b = p[k].y - p[i].y;
if (fabs(x*b-y*a) < 1e-6) {
++cnt;
}
}
ret = max(ret, cnt);
}
}
}
printf("Case %d: %d\n", ++ca, ret);
}
return 0;
}