Submission #1561069

---

Source Code Expand

#include<bits/stdc++.h>
using namespace std;
const int N = 200;
const int mod = 998244353;
int x[N],y[N];
typedef pair<int,int> pii;
int C(int i,int j){
	return x[i]*y[j]-x[j]*y[i];
}
int ccw(int i,int j,int k){
	return C(i,j)+C(j,k)+C(k,i);
}
int pp[N+1];
#define mul(x,y) ((long long)(x)*(y)%mod)
int main(){
	int n;scanf("%d",&n);
	pp[0]=1;for(int i=1;i<=n;i++)pp[i]=mul(pp[i-1],2);
	for(int i=0;i<n;i++){
		scanf("%d%d",x+i,y+i);
	}
	int ans=pp[n];
	ans = (ans+mod-1)%mod;
	ans = (ans+mod-n)%mod;
	for(int i=0;i<n;i++){
		for(int j=0;j<i;j++){
			int r=n;
			pii a = min(pii(x[i],y[i]),pii(x[j],y[j]));
			pii b = max(pii(x[i],y[i]),pii(x[j],y[j]));
			for(int k=0;k<n;k++){
				if(ccw(i,j,k)==0 && a <= pii(x[k],y[k]) && pii(x[k],y[k])<=b)r--;
			}
			ans-=pp[n-2-r];
			if(ans<0)ans+=mod;
		}
	}
	printf("%d\n",ans);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:16:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  int n;scanf("%d",&n);
                      ^
./Main.cpp:19:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",x+i,y+i);
                        ^

Judge Result