Submission #457514

#	Time	Username	Problem	Language	Result	Execution time	Memory
457514		hhhhaura	Triangles (CEOI18_tri)	C++14	0 / 100	1 ms	308 KiB

tri

#define wiwihorz
#pragma GCC optimize("Ofast")
#pragma loop-opt(on)
#include <bits/stdc++.h>
#include "trilib.h"
#define rep(i, a, b) for(int i = a; i <= b; i ++)
#define rrep(i, a, b) for(int i = b; i >= a; i--)
#define all(x) x.begin(), x.end()
using namespace std;

#ifdef wiwihorz
#define print(a...) cerr << "Line " << __LINE__ <<": ", kout("[" + string(#a) + "] = ", a)
void kout() {cerr << endl;}
void vprint(auto L, auto R) { while(L < R) cerr << *L << " \n"[next(L) == R], ++L;}
template<class T1, class ... T2> void kout(T1 a, T2 ... e) { cerr << a << " ", kout(e...); }
#else
#define print(...) 0
#define vprint(...) 0
#endif
namespace solver {
	vector<int> a, b, vis;
	void solve() {
		int n = get_n();
		vis.assign(n + 1, 0);
		rep(i, 1, n) a.push_back(i);
		sort(all(a), [](int x, int y) {
			if(x == 1 || y == 1) return (x == 1 ? 1 : 0);
			else return is_clockwise(x, 1, y);
		});
		for(auto i : a) {
			while(b.size() > 1 && !is_clockwise(
				b[b.size() - 1], b[b.size() - 2], i)) b.pop_back();
			b.push_back(i);
		}
		int cnt = 0, ft = 0, bk = b.size() - 1;
		while(++cnt && bk - ft + 1 > 3) {
			if(cnt & 1) {
				if(vis[b[ft + 1]]) break;
				vis[b[ft + 1]] = 1;
				while(bk - ft + 1 > 3 && 
					is_clockwise(b[ft], b[ft + 1], b[bk])) ft++;
			}
			else {
				if(vis[b[bk - 1]]) break;
				vis[b[bk - 1]] = 1;			
				while(bk - ft + 1 > 3 &&
					!is_clockwise(b[bk], b[bk - 1], b[ft])) bk --;
			}
		}
		give_answer(bk - ft + 1);
	}
};
using namespace solver;
signed main() {
	ios::sync_with_stdio(false), cin.tie(0);
	solve();
	return 0;
}

Compilation message (stderr)

tri.cpp:3: warning: ignoring '#pragma loop ' [-Wunknown-pragmas]
    3 | #pragma loop-opt(on)
      | 
tri.cpp:14:13: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   14 | void vprint(auto L, auto R) { while(L < R) cerr << *L << " \n"[next(L) == R], ++L;}
      |             ^~~~
tri.cpp:14:21: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   14 | void vprint(auto L, auto R) { while(L < R) cerr << *L << " \n"[next(L) == R], ++L;}
      |                     ^~~~

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