Submission #1632041

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Source Code Expand

#include<cstdio>
#include<algorithm>
using namespace std;
const int N=220,P=998244353;
int i,j,k,n,m,ch,ans,g;
int tm2[N];
struct point {
	int x,y;
	bool operator < (const point &n) const {
		if (x==n.x) return y<n.y;
		return x<n.x;
	}
} A[N],B[N];
void R(int &x) {
	x=0;ch=getchar();
	while (ch<'0' || '9'<ch) ch=getchar();
	while ('0'<=ch && ch<='9') x=x*10+ch-'0',ch=getchar();
}
int gcd(int a,int b) {
	if (!b) return a;
	return gcd(b,a%b);
}
int main() {
	R(n);
	tm2[0]=1;
	for (i=1;i<=n;i++) tm2[i]=(tm2[i-1]+tm2[i-1])%P;
	for (i=1;i<=n;i++) R(A[i].x),R(A[i].y);
	sort(A+1,A+n+1);
	ans=1;
	for (i=1;i<=n;i++) {
		m=0;
		ans=(ans+1)%P;
		for (j=i+1;j<=n;j++) {
			m++;
			B[m].x=A[j].x-A[i].x;
			B[m].y=A[j].y-A[i].y;
			if (B[m].y<0) g=gcd(B[m].x,-B[m].y);
			else g=gcd(B[m].x,B[m].y);
			B[m].x/=g;
			B[m].y/=g;
		}
		sort(B+1,B+m+1);
		B[m+1].x=-1;
		k=1;
		for (j=1;j<=m;j++) {
			if (B[j].x==B[j+1].x && B[j].y==B[j+1].y) k++;
			else {
				ans=(ans+tm2[k]-1)%P;
				k=1;
			}
		}
	}
	ans=(tm2[n]+P-ans)%P;
	printf("%d\n",ans);
}

Submission Info

Judge Result