Submission #1958288

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Source Code Expand

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <ctime>

#define Rep(i, n) for (int i = 1; i <= n; i ++)
#define Rep0(i, n) for (int i = 0; i <= n; i ++)
#define RepG(i, x) for (int i = head[x]; i; i = edge[i].next)
#define v edge[i].to
#define mp(a, b) make_pair(a, b)

using namespace std;

typedef long long LL;
const int N = 210;
const int mod = 998244353;

int x[N], y[N];
bool vis[N];

LL qpow(LL a, LL b)
{
	LL ret = 1, base = a;
	while (b) {
		if (b & 1) ret = ret * base % mod;
		base = base * base % mod, b >>= 1;
	}
	return ret;
}

int main()
{
	int n;
	scanf("%d", &n);
	Rep(i, n)scanf("%d%d", &x[i], &y[i]);
	
	LL ans = qpow(2, n);
	Rep(i, n) Rep(j, n) if (i != j){
		int cnt = 2;
		Rep(k, n) if (k != i && k != j)
			if ((y[j] - y[i]) * (x[k] - x[i]) == (y[k] - y[i]) * (x[j] - x[i])) cnt ++;
		LL tmp = (qpow(2, cnt) - 1 - cnt + mod) % mod;
		ans = (ans - tmp * qpow(cnt * (cnt - 1), mod - 2) % mod + mod) % mod;
		//printf("%lld %d\n", tmp, cnt * (cnt - 1));
	}
	
	ans = (ans - n - 1 + mod) % mod;
	printf("%lld\n", ans);
	
	
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:34:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
./Main.cpp:35:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  Rep(i, n)scanf("%d%d", &x[i], &y[i]);
                                      ^

Judge Result