Submission #1567677

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define mod 998244353

long long X[300], Y[300], P[300];
int N;

int main() {
    // freopen("input.in","r",stdin);
    // freopen("output.out","w",stdout);

    cin>>N;
    for(int i = 0;i < N;i++) cin>>X[i]>>Y[i];
    P[0] = 1;
    for(int i = 1;i <= N;i++) P[i] = (2*P[i-1]) % mod;

    long long answer = (P[N]-1-N+mod) % mod;
    // cout << answer << endl;

    for(int i = 0;i < N;i++) {
        for(int j = i+1;j < N;j++) {
            int counter = 0;
            for(int k = j+1;k < N;k++) {
                if((Y[j]-Y[i])*(X[k]-X[i]) == (Y[k]-Y[i])*(X[j]-X[i])) {
                    counter += 1;
                }
            }

            answer = (answer - P[counter] + mod) % mod;
        }
    }

    cout << answer << endl;

    return 0;
}

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