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답안 #230852

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
230852 2020-05-11T22:36:43 Z frodakcin Relay (COI16_relay) C++11
57 / 100
 145 ms 14456 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=z,r=M+z;
			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;
		u%=M;
		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 8 ms 6528 KB Output is correct
3 Correct 8 ms 6528 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 8 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 7 ms 6656 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 8 ms 6528 KB Output is correct
3 Correct 8 ms 6528 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 8 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 7 ms 6656 KB Output is correct
10 Correct 8 ms 6528 KB Output is correct
11 Correct 10 ms 6784 KB Output is correct
12 Correct 10 ms 6784 KB Output is correct
13 Correct 9 ms 6656 KB Output is correct
14 Correct 10 ms 6784 KB Output is correct
15 Correct 11 ms 6656 KB Output is correct
16 Correct 10 ms 6656 KB Output is correct
17 Correct 12 ms 6656 KB Output is correct
18 Correct 10 ms 6784 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 8 ms 6528 KB Output is correct
3 Correct 8 ms 6528 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 8 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 7 ms 6656 KB Output is correct
10 Correct 8 ms 6528 KB Output is correct
11 Correct 53 ms 7800 KB Output is correct
12 Correct 54 ms 7800 KB Output is correct
13 Correct 49 ms 7800 KB Output is correct
14 Correct 50 ms 7800 KB Output is correct
15 Correct 64 ms 7800 KB Output is correct
16 Correct 63 ms 7776 KB Output is correct
17 Correct 64 ms 7928 KB Output is correct
18 Correct 64 ms 7928 KB Output is correct
19 Correct 61 ms 7800 KB Output is correct
20 Correct 61 ms 7932 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 8 ms 6528 KB Output is correct
3 Correct 8 ms 6528 KB Output is correct
4 Correct 8 ms 6528 KB Output is correct
5 Correct 7 ms 6528 KB Output is correct
6 Correct 8 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 7 ms 6656 KB Output is correct
10 Correct 8 ms 6528 KB Output is correct
11 Correct 10 ms 6784 KB Output is correct
12 Correct 10 ms 6784 KB Output is correct
13 Correct 9 ms 6656 KB Output is correct
14 Correct 10 ms 6784 KB Output is correct
15 Correct 11 ms 6656 KB Output is correct
16 Correct 10 ms 6656 KB Output is correct
17 Correct 12 ms 6656 KB Output is correct
18 Correct 10 ms 6784 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 7800 KB Output is correct
22 Correct 54 ms 7800 KB Output is correct
23 Correct 49 ms 7800 KB Output is correct
24 Correct 50 ms 7800 KB Output is correct
25 Correct 64 ms 7800 KB Output is correct
26 Correct 63 ms 7776 KB Output is correct
27 Correct 64 ms 7928 KB Output is correct
28 Correct 64 ms 7928 KB Output is correct
29 Correct 61 ms 7800 KB Output is correct
30 Correct 61 ms 7932 KB Output is correct
31 Correct 108 ms 7800 KB Output is correct
32 Correct 108 ms 7928 KB Output is correct
33 Correct 85 ms 7928 KB Output is correct
34 Correct 85 ms 7928 KB Output is correct
35 Correct 145 ms 8056 KB Output is correct
36 Correct 142 ms 8060 KB Output is correct
37 Correct 135 ms 8056 KB Output is correct
38 Correct 133 ms 7928 KB Output is correct
39 Runtime error 90 ms 14456 KB Execution killed with signal 11 (could be triggered by violating memory limits)
40 Halted 0 ms 0 KB -