Submission #410735

#	Time	Username	Problem	Language	Result	Execution time	Memory
410735		maximath_1	Star triangles (IZhO11_triangle)	C++11	100 / 100	358 ms	12136 KiB

triangle

#include <bits/stdc++.h>

#define kyou using
#define mo namespace
#define kawaii std
 
kyou mo kawaii;
 
#define ll long long
#define ld long double
#define endl "\n"
const int MX = 2005;
const int LG = (int)log2(MX) + 1;
const int BLOCK = 205;
const int inf = 1000000069;
const ll inf_ll = 8000000000000000069ll;
const ld inf_ld = (ld)inf_ll;
const ld eps = 1e-9;
const ll mod = 1000000007;
const int alpha = 30;
const int dxh[] = {1, 1, -1, -1, 2, 2, -2, -2};
const int dyh[] = {2, -2, 2, -2, 1, -1, 1, -1}; // horse
const int dx[] = {1, -1, 0, 0, 0, 0};
const int dy[] = {0, 0, 1, -1, 0, 0}; // adj
const int dz[] = {0, 0, 0, 0, 1, -1}; // 3d
const int dxd[] = {1, 1, 1, 0, -1, -1, -1, 0};
const int dyd[] = {1, 0, -1, -1, -1, 0, 1, 1}; // diag
mt19937 rng(time(NULL));
 
bool untied = 0;
void setIn(string s){freopen(s.c_str(), "r", stdin);}
void setOut(string s){freopen(s.c_str(), "w", stdout);}
void unsyncIO(){cin.tie(0) -> sync_with_stdio(0);}
void setIO(string s = ""){
    if(!untied) unsyncIO(), untied = 1;
    if(s.size()){
        setIn(s + ".in");
        setOut(s + ".out");
    }
}

map<int, int> cntX, cntY;

int main(){
	setIO();
	int n; cin >> n;

	vector<pair<int, int> > pt(n);
	for(int i = 0; i < n; i ++){
		cin >> pt[i].first >> pt[i].second;
		cntX[pt[i].first] ++;
		cntY[pt[i].second] ++;
	}

	ll ans = 0ll;
	for(int i = 0; i < n; i ++)
		ans += (cntX[pt[i].first] - 1) * 1ll * (cntY[pt[i].second] - 1);
	cout << ans << endl;
	return 0;
}

Compilation message (stderr)

triangle.cpp: In function 'void setIn(std::string)':
triangle.cpp:31:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 | void setIn(string s){freopen(s.c_str(), "r", stdin);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp: In function 'void setOut(std::string)':
triangle.cpp:32:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 | void setOut(string s){freopen(s.c_str(), "w", stdout);}
      |                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100