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답안 #230846

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
230846 2020-05-11T22:30:47 Z frodakcin Relay (COI16_relay) C++11
57 / 100
 72 ms 6904 KB 
#include <cstdio>
#include <cassert>

using ll = long long;
struct vec
{
public:
	ll x, y;
	vec(ll x=0, ll y=0) : x(x), y(y) {}
	void in(){scanf("%lld%lld", &x, &y);}
	ll operator / (vec o) const {return x*o.y-o.x*y;}
	ll operator * (vec o) const {return x*o.x+y*o.y;}

	vec& operator += (vec o) {return x+=o.x, y+=o.y, *this;}
	vec& operator -= (vec o) {return x-=o.x, y-=o.y, *this;}

	friend vec operator + (vec a, vec b) {return a += b;}
	friend vec operator - (vec a, vec b) {return a -= b;}
};

const int MN = 1e5 + 10;
int N, M, low[MN], high[MN], ans;
bool mayday[MN];
vec a[MN], b[MN];
struct ray
{
public: 
	vec s, d;
};
ray bot, top;
int main(void)
{
	scanf("%d", &N);
	for(int i=0;i<N;++i)
		a[i].in();
	scanf("%d", &M);
	for(int i=0;i<M;++i)
		b[i].in(), b[i+M]=b[i];//for convenience
	for(int i=0,l,r,m,u,v,z;i<N;++i)
	{
		vec x=a[i];
		//printf("INFO FOR (id: %d), (%lld, %lld) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n", i+1, x.x, x.y);
		z=0;
		vec d=b[z]-x;
		if(d/(b[1]-b[0]) == 0)
			d=b[++z]-x;
		if(d/(b[z+1]-b[z]) > 0)
		{
			l=0,r=M;
			for(;r-l>1;)
			{
				m=l+(r-l)/2;
				if(d/(b[m]-b[z]) < 0)
					r=m;
				else
					l=m;
			}
			u=l;
		}
		else
			u=z;
		assert((b[u]-x)/(b[u+1]-x) <= 0);

		//b[u] is on the same side as a[i]
		d=b[u]-x;
		l=u,r=u+M;
		for(;r-l>1;)
		{
			m=l+(r-l)/2;
			if(d/(b[m]-b[u]) < 0)
				l=m;
			else
				r=m;
		}
		v=l;

		//printf("VALS: %d %d\n", u, v);
		assert((b[v]-x)/(b[v+1]-x) >= 0);

		//u<->v cut the convex hull
		//u is on closer side
		//lower hull: v...u
		{
			l=v,r=u;
			if(r<l)r+=M;
			--l;
			for(;r-l>1;)
			{
				m=l+(r-l)/2;
				if((b[m]-x)/(b[m+1]-b[m])>0)
					l=m;
				else
					r=m;
			}
			low[i] = r%M;
		}
		//upper hull: u...v
		{
			l=u,r=v;
			if(r<l) r+=M;
			--l;
			for(;r-l>1;)
			{
				m=l+(r-l)/2;
				if((b[m]-x)/(b[m+1]-b[m])<=0)
					l=m;
				else
					r=m;
			}
			high[i] = r%M;
		}

		//printf("\tLOW: (%lld, %lld)\n", b[low[i]].x, b[low[i]].y);
		//printf("\tHIGH: (%lld, %lld)\n", b[high[i]].x, b[high[i]].y);
		//printf("\n");

		assert((b[low[i]]-x)/(b[low[i]+1]-b[low[i]]) <= 0);
		assert((b[low[i]+M-1]-x)/(b[low[i]]-b[low[i]+M-1]) > 0);

		assert((b[high[i]]-x)/(b[high[i]+1]-b[high[i]]) > 0);
		assert((b[high[i]+M-1]-x)/(b[high[i]]-b[high[i]+M-1]) <= 0);
	}
	bot = {b[low[0]], b[low[0]]-a[0]};
	top = {b[high[0]], b[high[0]]-a[0]};
	vec bot0 = b[low[0]]-a[0];
	vec top0 = b[high[0]]-a[0];
	for(int i=1;i<N;++i)
	{
		if(bot.d/(a[i]-bot.s)>=0 || top.d/(a[i]-top.s)<=0)
			mayday[i] = 1;
		else if((a[i]-top.s)/(a[i]-bot.s) >= 0)
			mayday[i] = 1;
	}
	for(int i=1;i<N;++i)
		if(mayday[i])
		{
			//printf("MAYDAY: (id: %d), (%lld, %lld)\n", i+1, a[i].x, a[i].y);
			ray bot2 = {b[low[i]], b[low[i]]-a[i]};
			ray top2 = {b[high[i]], b[high[i]]-a[i]};

			if(bot0/bot2.d <= 0 && bot.d/bot2.d < 0)
				bot = bot2;
			if(top0/top2.d >= 0 && top.d/top2.d > 0)
				top = top2;
		}
	if((top.s-a[0])/(bot.s-a[0]) <= 0)
		return printf("%d\n", N-1), 0;
	for(int i=1;i<N;++i)
	{
		bool relay=0;
		if(bot.d/(a[i]-bot.s)>=0 || top.d/(a[i]-top.s)<=0)
			relay = 1;
		else if((a[i]-top.s)/(a[i]-bot.s) >= 0)
			relay = 1;
		if(relay)
		{
			++ans;
			//printf("RELAY: (id: %d), (%lld, %lld)\n", i+1, a[i].x, a[i].y);
		}
	}
	printf("%d\n", ans);
	return 0;
}

Compilation message

relay.cpp: In function 'int main()':
relay.cpp:33:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
relay.cpp:36:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &M);
  ~~~~~^~~~~~~~~~
relay.cpp: In member function 'void vec::in()':
relay.cpp:10:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  void in(){scanf("%lld%lld", &x, &y);}
            ~~~~~^~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3456 KB Output is correct
2 Correct 6 ms 3456 KB Output is correct
3 Correct 6 ms 3456 KB Output is correct
4 Correct 6 ms 3456 KB Output is correct
5 Correct 6 ms 3456 KB Output is correct
6 Correct 6 ms 3456 KB Output is correct
7 Correct 8 ms 3456 KB Output is correct
8 Correct 6 ms 3456 KB Output is correct
9 Correct 6 ms 3456 KB Output is correct
10 Correct 6 ms 3456 KB Output is correct

Subtask #2
19.0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3456 KB Output is correct
2 Correct 6 ms 3456 KB Output is correct
3 Correct 6 ms 3456 KB Output is correct
4 Correct 6 ms 3456 KB Output is correct
5 Correct 6 ms 3456 KB Output is correct
6 Correct 6 ms 3456 KB Output is correct
7 Correct 8 ms 3456 KB Output is correct
8 Correct 6 ms 3456 KB Output is correct
9 Correct 6 ms 3456 KB Output is correct
10 Correct 6 ms 3456 KB Output is correct
11 Correct 9 ms 3584 KB Output is correct
12 Correct 9 ms 3584 KB Output is correct
13 Correct 8 ms 3584 KB Output is correct
14 Correct 8 ms 3584 KB Output is correct
15 Correct 10 ms 3584 KB Output is correct
16 Correct 9 ms 3584 KB Output is correct
17 Correct 9 ms 3584 KB Output is correct
18 Correct 9 ms 3584 KB Output is correct
19 Correct 8 ms 3584 KB Output is correct
20 Correct 8 ms 3584 KB Output is correct

Subtask #3
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3456 KB Output is correct
2 Correct 6 ms 3456 KB Output is correct
3 Correct 6 ms 3456 KB Output is correct
4 Correct 6 ms 3456 KB Output is correct
5 Correct 6 ms 3456 KB Output is correct
6 Correct 6 ms 3456 KB Output is correct
7 Correct 8 ms 3456 KB Output is correct
8 Correct 6 ms 3456 KB Output is correct
9 Correct 6 ms 3456 KB Output is correct
10 Correct 6 ms 3456 KB Output is correct
11 Correct 52 ms 4472 KB Output is correct
12 Correct 57 ms 4448 KB Output is correct
13 Correct 49 ms 4416 KB Output is correct
14 Correct 50 ms 4472 KB Output is correct
15 Correct 63 ms 4600 KB Output is correct
16 Correct 62 ms 4472 KB Output is correct
17 Correct 62 ms 4472 KB Output is correct
18 Correct 62 ms 4472 KB Output is correct
19 Correct 60 ms 4600 KB Output is correct
20 Correct 61 ms 4472 KB Output is correct

Subtask #4
0 / 43.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 3456 KB Output is correct
2 Correct 6 ms 3456 KB Output is correct
3 Correct 6 ms 3456 KB Output is correct
4 Correct 6 ms 3456 KB Output is correct
5 Correct 6 ms 3456 KB Output is correct
6 Correct 6 ms 3456 KB Output is correct
7 Correct 8 ms 3456 KB Output is correct
8 Correct 6 ms 3456 KB Output is correct
9 Correct 6 ms 3456 KB Output is correct
10 Correct 6 ms 3456 KB Output is correct
11 Correct 9 ms 3584 KB Output is correct
12 Correct 9 ms 3584 KB Output is correct
13 Correct 8 ms 3584 KB Output is correct
14 Correct 8 ms 3584 KB Output is correct
15 Correct 10 ms 3584 KB Output is correct
16 Correct 9 ms 3584 KB Output is correct
17 Correct 9 ms 3584 KB Output is correct
18 Correct 9 ms 3584 KB Output is correct
19 Correct 8 ms 3584 KB Output is correct
20 Correct 8 ms 3584 KB Output is correct
21 Correct 52 ms 4472 KB Output is correct
22 Correct 57 ms 4448 KB Output is correct
23 Correct 49 ms 4416 KB Output is correct
24 Correct 50 ms 4472 KB Output is correct
25 Correct 63 ms 4600 KB Output is correct
26 Correct 62 ms 4472 KB Output is correct
27 Correct 62 ms 4472 KB Output is correct
28 Correct 62 ms 4472 KB Output is correct
29 Correct 60 ms 4600 KB Output is correct
30 Correct 61 ms 4472 KB Output is correct
31 Runtime error 72 ms 6904 KB Execution killed with signal 11 (could be triggered by violating memory limits)
32 Halted 0 ms 0 KB -