Submission #879499

#	Time	Username	Problem	Language	Result	Execution time	Memory
879499		Mr_Husanboy	Star triangles (IZhO11_triangle)	C++17	100 / 100	337 ms	24912 KiB

triangle

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



#ifdef LOCAL
#include "debugger.cpp"
#else
#define debug(...)
#endif
template<class T>
int len(T &a){
    return a.size();
}

using ll = long long;
using pii = pair<int,int>;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
string fileio = "";


mt19937 mt(time(nullptr));
const int mod = 1e9 + 7;
const int inf = 1e9;
const ll infl = 1e18;
const int maxn = 1e5 + 1;





void solve(){
    int n; cin >> n;
    ll ans =0;
    set<pair<int,int>> st;
    for(int i = 0; i < n; i ++){
        int x, y; cin >> x >> y;
        st.insert({x, y});
    }
    map<int,vector<int>> mp;
    map<int,int> cnt;
    for(auto [x, y] : st){
        mp[y].push_back(x);
        cnt[x] ++;
    }

    for(auto [_, vec] : mp){
        ll k = len(vec);
        for(auto u : vec){
            ans += (k - 1) * (cnt[u] - 1);
        }
    }
    cout << ans;
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    auto start = chrono::high_resolution_clock::now();
    #ifndef LOCAL
    if(fileio.size()){
        freopen((fileio + ".in").c_str(), "r", stdin);
        freopen((fileio + ".out").c_str(), "w", stdout);
    }
    #endif
    int testcases = 1;
    #ifdef Tests
    cin >> testcases;
    #endif
    while(testcases --){
        solve();
        cout << '\n';
        #ifdef LOCAL
        cout << "_________________________" << endl;
        #endif
    }
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    
    cout << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
    return 0;
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:60:10: warning: variable 'start' set but not used [-Wunused-but-set-variable]
   60 |     auto start = chrono::high_resolution_clock::now();
      |          ^~~~~
triangle.cpp:63:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen((fileio + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen((fileio + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100