Submission #1306995

#	Time	Username	Problem	Language	Result	Execution time	Memory
1306995		abyfu	Star triangles (IZhO11_triangle)	C++20	100 / 100	250 ms	7036 KiB

triangle

//OwO
//#pragma GCC optimize("O3", "unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define namein "input.txt"
#define nameout "output.txt"
#define pque priority_queue
#define all(x) x.begin(),x.end()
#define fi first
#define se second
#define pb push_back
#define m_pi acos(-1)
using namespace std;
const ll inf = 4e18;    
const int linf = 1.5e9;

void file(){
    if (fopen(namein, "r")){
        freopen(namein, "r", stdin);
        freopen(nameout, "w", stdout);
    }   
}


const ll mod = 1e9 + 7;
const int N = 3e5 + 5, M = 5e1 + 5;
map<ll, ll> x, y;
int a[N], b[N];

void run(){
    int n; cin >> n;
    for (int i = 1; i <= n; i++){
        cin >> a[i] >> b[i];
        x[a[i]]++; y[b[i]]++;
    }    
    ll as = 0;
    for (int i = 1; i <= n; i++){
        as += (x[a[i]] - 1)*(y[b[i]] - 1);
        //cout << (x[a[i]] - 1)*(y[b[i]] - 1) << " " << a[i] << " " << b[i] << "\n";
    }
    cout << as;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); 
    cout.tie(0);
    file();
    run();
}

Compilation message (stderr)

triangle.cpp: In function 'void file()':
triangle.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         freopen(namein, "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
triangle.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(nameout, "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100