Submission #1817223

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Source Code Expand

#include <algorithm>
#include <cstdio>
const int N=205,mo=998244353;
int pw[N],s;
struct P{
	int x,y;
	P(const int xx=0,const int yy=0):x(xx),y(yy){}
}p[N];
P operator -(P a,P b){return P(a.x-b.x,a.y-b.y);}
int operator *(P a,P b){return a.x*b.y-a.y*b.x;}
bool operator <(P a,P b){return a.x!=b.x?a.x<b.x:a.y<b.y;}
bool cmp(P a,P b){return (a-p[s])*(b-p[s])<0;}
int main(){
	int n;
	scanf("%d\n",&n);
	for (int i=1;i<=n;i++) scanf("%d%d",&p[i].x,&p[i].y);
	pw[0]=1;
	for (int i=1;i<=n;i++) pw[i]=pw[i-1]*2%mo;
	int ans=pw[n]-n-1;
	for (int i=1;i<=n;i++){
		s=i;
		for (int j=i+1;j<=n;j++)
			if (p[j]<p[s]) s=j;
		std::swap(p[i],p[s]);s=i;
		std::sort(p+i+1,p+n+1,cmp);
		for (int j=i+1,k=i+1;j<=n;j=k){
			for (;k<=n && (p[j]-p[i])*(p[k]-p[i])==0;k++);
			(ans-=pw[k-j]-1)%=mo;
		}
	}
	printf("%d\n",(ans+mo)%mo);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:15:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d\n",&n);
                  ^
./Main.cpp:16:54: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for (int i=1;i<=n;i++) scanf("%d%d",&p[i].x,&p[i].y);
                                                      ^

Judge Result