Submission #1055107

#	Time	Username	Problem	Language	Result	Execution time	Memory
1055107		anango	Portal (BOI24_portal)	C++17	65 / 100	776 ms	2616 KiB

Main

#include <bits/stdc++.h>
#define int long long
using namespace std;
 
mt19937 rng;
#pragma GCC optimize("Ofast,fast-math")
 
vector<int> cords;
 
int area(int i, int j, int k) {
    return cords[2*i]*cords[2*j+1]-cords[2*i+1]*cords[2*j]+cords[2*j]*cords[2*k+1]-cords[2*j+1]*cords[2*k]+cords[2*k]*cords[2*i+1]-cords[2*k+1]*cords[2*i];
}
 
signed main() {
    rng.discard(time(NULL)%8888);
    int local = 0;
    if (local) {
        // for getting input from input.txt
        freopen("input.txt", "r", stdin);
        // for writing output to output.txt
        freopen("output.txt", "w", stdout);
    }
    #ifdef ONLINE_JUDGE
    	ios_base::sync_with_stdio(false);
    	cin.tie(NULL);
    #endif //fast IO
    int n; cin >> n;
    for (int i=0; i<n; i++) {
        int x,y; cin >> x >> y; 
        cords.push_back(x); cords.push_back(y);
    }
    int g = 0;
    /*for (int it=0; it<100000000; it++) {
        int j,k;
        j=rng()%n; k=rng()%n;
        //cout << i <<" " << j <<" " << k <<" " << area(i,j,k) << endl;
        
    }*/
    if (n<10000) {
        for (int j=0; j<n; j++) {
            for (int k=0; k<n; k++) {
                g=gcd(g,area(0,j,k));
            }
        }
    }
    else {
        for (int j=0; j<3; j++) {
            int root=rng()%n;
            for (int it=0; it<10000000; it++) {
                int j,k;
                j=rng()%n; k=rng()%n;
                //cout << i <<" " << j <<" " << k <<" " << area(i,j,k) << endl;
                g=gcd(g,area(root,j,k));
            }
        }
    }
    g=abs(g);
    if (g==0) {
        cout << -1 << endl;
    }
    else {
        cout << g << endl;
    }
    
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:19:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 29 / 29
• Subtask 5: 15 / 15
• Subtask 6: 0 / 35