Submission #1561994

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Source Code Expand

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

#define F first
#define S second
#define int long long
#define ull  unsigned long long
#define pb push_back

using namespace std;
using namespace __gnu_pbds;
typedef  tree< int , null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

const int N = 110000;
int p[N], x[N], y[N];
const int mod = 998244353;
main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    //freopen("input.txt",  "r", stdin);
    //freopen("output.txt", "w", stdout);
    int n;
    cin >> n;
    p[0] = 1;
    for (int i = 1; i <= n; i++){
        p[i] = (p[i - 1] + p[i - 1]) % mod;
    }
    for (int i = 1; i <= n; i++){
        cin >> x[i] >> y[i];
    }
    int ans = 0;
    for (int i = 1; i <= n; i++){
        for (int j = i + 1; j <= n; j++){
            int k = 0;
            for (int l = j + 1; l <= n; l++){
                if ((x[l] - x[j]) * (y[j] - y[i]) == (x[j] - x[i]) * (y[l] - y[j])) k++;
            }
            ans = (ans + p[k]) % mod;
        }
    }
    ans = (p[n] - ans + mod - n - 1 + mod) % mod;
    cout << ans;
}

Submission Info

Judge Result