oj.uz

Submission #167095

# Submission time Handle Problem Language Result Execution time Memory
167095 2019-12-05T14:37:48 Z cgiosy None (KOI18_footprint) C++17
14 / 100
 57 ms 504 KB 
#include <bits/stdc++.h>
#define rep(i,x,n) for(int i=x; i<n; i++)
using namespace std;

struct pii {
	int x, y;
	bool operator<(const pii b) const { return y<b.y || (y==b.y && x<b.x); }
	pii operator-(const pii b) const { return {x-b.x, y-b.y}; }
};
long cross(pii a, pii b) { return a.x*long(b.y)-a.y*long(b.x); }
long ccw(pii o, pii a, pii b) { return cross(o-a, o-b); }
int main() {
	ios_base::sync_with_stdio(false);cin.tie(nullptr);
	int N;
	cin>>N;
	vector<pii> A(N);
	for(auto&[x,y]:A) cin>>x>>y;
	swap(A[0], *min_element(begin(A), end(A)));
	sort(begin(A)+1, end(A), [&](pii x, pii y) { return ccw(A[0], x, y)<0; });
	vector<pii> D1(N), D2(N);
	int a=0, c=0;
	rep(i, 1, N) D2[i]={2, 0};
	rep(i, 0, N) {
		rep(j, 0, i) {
			if(ccw(A[0], A[j], A[i])==0) continue;
			#define maxi(a, b, c) if(a.x<b.x+1) a={b.x+1, c}
			if(ccw(A[D2[j].y], A[j], A[i])<0) maxi(D1[i], D2[j], j);
			if(ccw(A[D1[j].y], A[j], A[i])>0) maxi(D2[i], D1[j], j);
		}
		if(D2[a].x<D2[i].x) a=i;
	}
	if(D2[a].x<4) {
		cout<<"0\n";
		return 0;
	}
	cout<<D2[a].x<<'\n'<<A[0].x<<' '<<A[0].y<<'\n';
	do cout<<A[a].x<<' '<<A[a].y<<'\n'; while(a=c++%2 ? D1[a].y : D2[a].y);
}

Compilation message

footprint.cpp: In function 'int main()':
footprint.cpp:37:45: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  do cout<<A[a].x<<' '<<A[a].y<<'\n'; while(a=c++%2 ? D1[a].y : D2[a].y);
                                            ~^~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 52 ms 504 KB Output is correct
2 Correct 53 ms 448 KB Output is correct
3 Correct 51 ms 504 KB Output is correct
4 Correct 51 ms 504 KB Output is correct
5 Correct 51 ms 504 KB Output is correct
6 Correct 51 ms 504 KB Output is correct
7 Correct 52 ms 504 KB Output is correct
8 Correct 51 ms 504 KB Output is correct
9 Correct 55 ms 376 KB Output is correct
10 Correct 54 ms 376 KB Output is correct
11 Correct 52 ms 476 KB Output is correct
12 Correct 57 ms 504 KB Output is correct
13 Correct 53 ms 504 KB Output is correct
14 Correct 52 ms 380 KB Output is correct
15 Correct 51 ms 504 KB Output is correct

Subtask #2
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 256 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 452 KB Output is correct
5 Correct 2 ms 256 KB Output is correct
6 Incorrect 2 ms 376 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 256 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 452 KB Output is correct
5 Correct 2 ms 256 KB Output is correct
6 Incorrect 2 ms 376 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #4
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 52 ms 504 KB Output is correct
2 Correct 53 ms 448 KB Output is correct
3 Correct 51 ms 504 KB Output is correct
4 Correct 51 ms 504 KB Output is correct
5 Correct 51 ms 504 KB Output is correct
6 Correct 51 ms 504 KB Output is correct
7 Correct 52 ms 504 KB Output is correct
8 Correct 51 ms 504 KB Output is correct
9 Correct 55 ms 376 KB Output is correct
10 Correct 54 ms 376 KB Output is correct
11 Correct 52 ms 476 KB Output is correct
12 Correct 57 ms 504 KB Output is correct
13 Correct 53 ms 504 KB Output is correct
14 Correct 52 ms 380 KB Output is correct
15 Correct 51 ms 504 KB Output is correct
16 Correct 2 ms 376 KB Output is correct
17 Correct 2 ms 256 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 452 KB Output is correct
20 Correct 2 ms 256 KB Output is correct
21 Incorrect 2 ms 376 KB Output isn't correct
22 Halted 0 ms 0 KB -