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Submission #120376

# Submission time Handle Problem Language Result Execution time Memory
120376 2019-06-24T09:27:45 Z tmwilliamlin168 Printed Circuit Board (CEOI12_circuit) C++14
100 / 100
 19 ms 4600 KB 
#include <bits/stdc++.h>
using namespace std;

int in() {
	char c=0;
	while(c<'0'||c>'9')
		c=getchar_unlocked();
	int r=0;
	while(c>='0'&&c<='9') {
		r=r*10+c-'0';
		c=getchar_unlocked();
	}
	return r;
}

void out(int x) {
	int c=0, r=0;
	for(; x%10==0; ++c, x/=10);
	for(; x; r=r*10+x%10, x/=10);
	for(; r; r/=10)
		putchar_unlocked('0'+r%10);
	while(c--)
		putchar_unlocked('0');
}

const int mxN=2e5;
int n, l, r;
long long x[mxN+1], y[mxN+1];
vector<int> v, s;
bool b[mxN];

int main() {
	auto cp=[](int a, int b, int c) {
		return (y[c]-y[a])*(x[b]-x[a])-(y[b]-y[a])*(x[c]-x[a]);
	};
	n=in();
	for(int i=0; i<n; ++i) {
		x[i]=in(), y[i]=in();
		if(!i||cp(n, l, i)>0||!cp(n, l, i)&&x[i]<x[l])
			l=i;
		if(!i||cp(n, r, i)<0||!cp(n, r, i)&&x[i]<x[r])
			r=i;
	}
	int ic=cp((l+n-1)%n, l, (l+1)%n)>0?1:n-1;
	for(; l^r; l=(l+ic)%n)
		v.push_back(l);
	v.push_back(r);
	s={0, 1};
	for(int i=2; i<v.size(); ++i) {
		auto ul=[&]() {
			while(cp(n, v[s.back()], v[i])>=0&&cp(v[i-1], v[i], v[s.back()])<=0)
				s.pop_back();
			for(int j=i, c=cp(n, v[s.back()], v[i])<0; cp(n, v[s.back()], v[i])>=0||!c; ++i) {
				if(i^j?cp(n, v[j], v[i])>=0&&cp(n, v[j], v[i+1])<0&&cp(v[i], v[i+1], v[j])>0:cp(n, v[i], v[i+1])<0&&cp(v[i-1], v[i], v[i+1])>0)
					++c;
				if(cp(n, v[j], v[i])<0&&cp(n, v[j], v[i+1])>=0&&cp(v[i], v[i+1], v[j])<0)
					--c;
			}
		};
		if(!cp(n, v[i-1], v[i])&&(cp(n, v[i-2], v[i-1])<0)==(cp(v[i-2], v[i-1], v[i])<0))
			s.pop_back();
		else if(cp(n, v[i-1], v[i])<=0&&cp(n, v[i-2], v[i-1])>0&&cp(v[i-2], v[i-1], v[i])<0) {
			while(cp(n, v[s.back()], v[i])<=0)
				++i;
			s.pop_back();
			ul();
		} else if(cp(n, v[i-1], v[i])>0&&(cp(n, v[i-2], v[i-1])>=0||cp(v[i-2], v[i-1], v[i])<0))
			ul();
		else if(cp(n, v[i-1], v[i])>=0)
			while(cp(n, v[s.back()], v[i])>=0)
				++i;
		s.push_back(i);
	}
	out(s.size());
	putchar_unlocked('\n');
	for(int a : s)
		b[v[a]]=1;
	for(int i=0; i<n; ++i) {
		if(b[i]) {
			out(i+1);
			putchar_unlocked(' ');
		}
	}
}

Compilation message

circuit.cpp: In function 'int main()':
circuit.cpp:39:37: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(!i||cp(n, l, i)>0||!cp(n, l, i)&&x[i]<x[l])
                         ~~~~~~~~~~~~^~~~~~~~~~~
circuit.cpp:41:37: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(!i||cp(n, r, i)<0||!cp(n, r, i)&&x[i]<x[r])
                         ~~~~~~~~~~~~^~~~~~~~~~~
circuit.cpp:49:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=2; i<v.size(); ++i) {
               ~^~~~~~~~~

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 384 KB Output is correct
2 Correct 2 ms 384 KB Output is correct
3 Correct 3 ms 512 KB Output is correct
4 Correct 2 ms 512 KB Output is correct
5 Correct 3 ms 640 KB Output is correct
6 Correct 2 ms 512 KB Output is correct
7 Correct 3 ms 768 KB Output is correct
8 Correct 3 ms 512 KB Output is correct
9 Correct 3 ms 640 KB Output is correct
10 Correct 3 ms 640 KB Output is correct
11 Correct 3 ms 640 KB Output is correct
12 Correct 3 ms 892 KB Output is correct
13 Correct 5 ms 1024 KB Output is correct
14 Correct 4 ms 1152 KB Output is correct
15 Correct 5 ms 1508 KB Output is correct
16 Correct 9 ms 2556 KB Output is correct
17 Correct 10 ms 2304 KB Output is correct
18 Correct 15 ms 4600 KB Output is correct
19 Correct 16 ms 4600 KB Output is correct
20 Correct 19 ms 4600 KB Output is correct