Submission #121123

#	Time	Username	Problem	Language	Result	Execution time	Memory
121123		RockyB	Triangles (CEOI18_tri)	C++17	35 / 100	24 ms	384 KiB

tri

/// In The Name Of God
 
#include <bits/stdc++.h>
#include "trilib.h"
 
#define f first
#define s second
 
#define pb push_back
#define pp pop_back
#define mp make_pair
 
#define sz(x) (int)x.size()
#define sqr(x) ((x) * 1ll * (x))
#define all(x) x.begin(), x.end()
 
#define rep(i, l, r) for (int i = (l); i <= (r); i++)
#define per(i, l, r) for (int i = (l); i >= (r); i--)
 
#define Kazakhstan ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);
 
#define nl '\n'
#define ioi exit(0);
 
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
 
const int N = (int)5e5 + 7;
const int inf = (int)1e9 + 7;
const int mod = (int)1e9 + 7;
const ll linf = (ll)1e18 + 7;
 
const int dx[] = {-1, 0, 1, 0, 1, -1, -1, 1};
const int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
 
using namespace std;
 
int n;
 
bool check(int i, int j) {
	set <int> st;
	for (int k = 1; k <= n; k++) {
		if (k == i || k == j) continue;
		st.insert(is_clockwise(i, j, k));
		if (sz(st) > 1) return 0;
	}
	return 1;
}

set < pair <int, int > > con;

int main() {
	#ifdef IOI2018
		freopen ("in.txt", "r", stdin);
	#endif
	n = get_n();
	set <int> st;
	rep(i, 1, n) {
		int cnt = 0;
		rep(j, i + 1, n) {
			if (con.count({i, j})) continue;
			if (check(i, j)) {
				st.insert(i), st.insert(j);
				con.insert({i, j});
				con.insert({j, i});
				++cnt;
				if (cnt == 2) break;
			}
		}
	}
	give_answer(sz(st));
	ioi
}

• Subtask 1: 15 / 15
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 20 / 20
• Subtask 5: 0 / 25