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답안 #230847

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
230847 2020-05-11T22:31:39 Z frodakcin Relay (COI16_relay) C++11
57 / 100
 140 ms 14200 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 = 2e5 + 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 8 ms 6528 KB Output is correct
2 Correct 9 ms 6656 KB Output is correct
3 Correct 8 ms 6656 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 7 ms 6528 KB Output is correct
7 Correct 8 ms 6528 KB Output is correct
8 Correct 7 ms 6528 KB Output is correct
9 Correct 8 ms 6528 KB Output is correct
10 Correct 8 ms 6528 KB Output is correct

Subtask #2
19.0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 6528 KB Output is correct
2 Correct 9 ms 6656 KB Output is correct
3 Correct 8 ms 6656 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 7 ms 6528 KB Output is correct
7 Correct 8 ms 6528 KB Output is correct
8 Correct 7 ms 6528 KB Output is correct
9 Correct 8 ms 6528 KB Output is correct
10 Correct 8 ms 6528 KB Output is correct
11 Correct 10 ms 6656 KB Output is correct
12 Correct 12 ms 6656 KB Output is correct
13 Correct 9 ms 6656 KB Output is correct
14 Correct 9 ms 6656 KB Output is correct
15 Correct 10 ms 6656 KB Output is correct
16 Correct 10 ms 6656 KB Output is correct
17 Correct 10 ms 6656 KB Output is correct
18 Correct 10 ms 6656 KB Output is correct
19 Correct 10 ms 6656 KB Output is correct
20 Correct 10 ms 6656 KB Output is correct

Subtask #3
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 6528 KB Output is correct
2 Correct 9 ms 6656 KB Output is correct
3 Correct 8 ms 6656 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 7 ms 6528 KB Output is correct
7 Correct 8 ms 6528 KB Output is correct
8 Correct 7 ms 6528 KB Output is correct
9 Correct 8 ms 6528 KB Output is correct
10 Correct 8 ms 6528 KB Output is correct
11 Correct 53 ms 7416 KB Output is correct
12 Correct 54 ms 7416 KB Output is correct
13 Correct 49 ms 7420 KB Output is correct
14 Correct 52 ms 7416 KB Output is correct
15 Correct 63 ms 7416 KB Output is correct
16 Correct 63 ms 7416 KB Output is correct
17 Correct 62 ms 7416 KB Output is correct
18 Correct 63 ms 7380 KB Output is correct
19 Correct 62 ms 7416 KB Output is correct
20 Correct 61 ms 7416 KB Output is correct

Subtask #4
0 / 43.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 6528 KB Output is correct
2 Correct 9 ms 6656 KB Output is correct
3 Correct 8 ms 6656 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 7 ms 6528 KB Output is correct
7 Correct 8 ms 6528 KB Output is correct
8 Correct 7 ms 6528 KB Output is correct
9 Correct 8 ms 6528 KB Output is correct
10 Correct 8 ms 6528 KB Output is correct
11 Correct 10 ms 6656 KB Output is correct
12 Correct 12 ms 6656 KB Output is correct
13 Correct 9 ms 6656 KB Output is correct
14 Correct 9 ms 6656 KB Output is correct
15 Correct 10 ms 6656 KB Output is correct
16 Correct 10 ms 6656 KB Output is correct
17 Correct 10 ms 6656 KB Output is correct
18 Correct 10 ms 6656 KB Output is correct
19 Correct 10 ms 6656 KB Output is correct
20 Correct 10 ms 6656 KB Output is correct
21 Correct 53 ms 7416 KB Output is correct
22 Correct 54 ms 7416 KB Output is correct
23 Correct 49 ms 7420 KB Output is correct
24 Correct 52 ms 7416 KB Output is correct
25 Correct 63 ms 7416 KB Output is correct
26 Correct 63 ms 7416 KB Output is correct
27 Correct 62 ms 7416 KB Output is correct
28 Correct 63 ms 7380 KB Output is correct
29 Correct 62 ms 7416 KB Output is correct
30 Correct 61 ms 7416 KB Output is correct
31 Correct 110 ms 7416 KB Output is correct
32 Correct 112 ms 7544 KB Output is correct
33 Correct 83 ms 7672 KB Output is correct
34 Correct 86 ms 7672 KB Output is correct
35 Correct 138 ms 7672 KB Output is correct
36 Correct 140 ms 7672 KB Output is correct
37 Correct 132 ms 7672 KB Output is correct
38 Correct 135 ms 7672 KB Output is correct
39 Runtime error 116 ms 14200 KB Execution killed with signal 11 (could be triggered by violating memory limits)
40 Halted 0 ms 0 KB -