oj.uz

Submission #242192

# Submission time Handle Problem Language Result Execution time Memory
242192 2020-06-27T05:25:02 Z arnold518 None (KOI18_footprint) C++14
14 / 100
 1010 ms 134008 KB 
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 3000;
const ll INF = 1e9;

struct Point { ll x, y; };
bool operator == (const Point &p, const Point &q) { return p.x==q.x && p.y==q.y; }
Point operator + (const Point &p, const Point &q) { return {p.x+q.x, p.y+q.y}; }
Point operator - (const Point &p, const Point &q) { return {p.x-q.x, p.y-q.y}; }

ll ccw(Point p, Point q) { return p.x*q.y-p.y*q.x; }
ll ccw(Point p, Point q1, Point q2) { return ccw(q1-p, q2-p); }

int N;
Point A[MAXN+10], P={INF, INF};

pii dp1[MAXN+10][MAXN+10], dp2[MAXN+10][MAXN+10];
pair<int, pii> ans;

int main()
{
	int i, j, k;

	scanf("%d", &N);
	for(i=1; i<=N; i++) scanf("%lld%lld", &A[i].x, &A[i].y);
	for(i=1; i<=N; i++) if(A[i].y<P.y) P=A[i];
	for(i=1; i<=N; i++) if(A[i]==P) break;
	for(; i<N; i++) swap(A[i], A[i+1]);

	N--;
	sort(A+1, A+N+1, [&](const Point &p, const Point &q) { return ccw(P, p, q)<0; });

	for(i=1; i<=N; i++)
	{
		vector<int> L, R;
		for(j=i+1; j<=N; j++) if(ccw(P, A[i], A[j])!=0) R.push_back(j), dp1[j][i+1]=dp2[j][i+1]={-987654321, 0};
		for(j=1; j<i; j++) if(ccw(P, A[i], A[j])!=0) L.push_back(j);

		sort(L.begin(), L.end(), [&](const int &p, const int &q) { return ccw(A[i]-A[p], A[i]-A[q])<0; });
		sort(R.begin(), R.end(), [&](const int &p, const int &q) { return ccw(A[p]-A[i], A[q]-A[i])<0; });

		pii now={2, i};
		for(j=0, k=0; j<R.size(); j++)
		{
			for(; k<L.size() && ccw(A[i]-A[L[k]], A[R[j]]-A[i])<=0; k++) now=max(now, {dp2[L[k]][i].first+1, L[k]});
			dp1[i][R[j]]=max(dp1[i][R[j]], now);
		}

		now={-987654321, 0};
		for(j=R.size()-1, k=L.size()-1; j>=0; j--)
		{
			for(; k>=0 && ccw(A[i]-A[L[k]], A[R[j]]-A[i])>=0; k--) now=max(now, {dp1[L[k]][i].first+1, L[k]});
			dp2[i][R[j]]=max(dp2[i][R[j]], now);
			ans=max(ans, {dp2[i][R[j]].first, {i, R[j]}});
		}
	}
	if(ans.first==0) return !printf("0\n");
	vector<Point> V;
	pii v=ans.second; int t=2;
	V.push_back(P);
	while(1)
	{
		V.push_back(A[v.second]);
		if(v.first==v.second) break;
		if(t==2)
		{
			v={dp2[v.first][v.second].second, v.first};
			t=1;
		}
		else
		{
			v={dp1[v.first][v.second].second, v.first};
			t=2;
		}
	}

	printf("%d\n", V.size());
	for(auto it : V) printf("%lld %lld\n", it.x, it.y);
}

Compilation message

footprint.cpp: In function 'int main()':
footprint.cpp:48:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(j=0, k=0; j<R.size(); j++)
                 ~^~~~~~~~~
footprint.cpp:50:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(; k<L.size() && ccw(A[i]-A[L[k]], A[R[j]]-A[i])<=0; k++) now=max(now, {dp2[L[k]][i].first+1, L[k]});
          ~^~~~~~~~~
footprint.cpp:82:25: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<Point>::size_type {aka long unsigned int}' [-Wformat=]
  printf("%d\n", V.size());
                 ~~~~~~~~^
footprint.cpp:29:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
footprint.cpp:30:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(i=1; i<=N; i++) scanf("%lld%lld", &A[i].x, &A[i].y);
                      ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 930 ms 129424 KB Output is correct
2 Correct 982 ms 131804 KB Output is correct
3 Correct 955 ms 130740 KB Output is correct
4 Correct 978 ms 131964 KB Output is correct
5 Correct 975 ms 131064 KB Output is correct
6 Correct 1000 ms 131904 KB Output is correct
7 Correct 962 ms 131576 KB Output is correct
8 Correct 996 ms 132184 KB Output is correct
9 Correct 971 ms 132344 KB Output is correct
10 Correct 980 ms 132088 KB Output is correct
11 Correct 978 ms 132064 KB Output is correct
12 Correct 1008 ms 132728 KB Output is correct
13 Correct 1010 ms 134008 KB Output is correct
14 Correct 990 ms 132088 KB Output is correct
15 Correct 975 ms 130952 KB Output is correct

Subtask #2
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 416 KB Output is correct
4 Correct 5 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 5 ms 384 KB Output is correct
9 Correct 5 ms 384 KB Output is correct
10 Incorrect 5 ms 384 KB Output isn't correct
11 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 416 KB Output is correct
4 Correct 5 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 5 ms 384 KB Output is correct
9 Correct 5 ms 384 KB Output is correct
10 Incorrect 5 ms 384 KB Output isn't correct
11 Halted 0 ms 0 KB -

Subtask #4
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 930 ms 129424 KB Output is correct
2 Correct 982 ms 131804 KB Output is correct
3 Correct 955 ms 130740 KB Output is correct
4 Correct 978 ms 131964 KB Output is correct
5 Correct 975 ms 131064 KB Output is correct
6 Correct 1000 ms 131904 KB Output is correct
7 Correct 962 ms 131576 KB Output is correct
8 Correct 996 ms 132184 KB Output is correct
9 Correct 971 ms 132344 KB Output is correct
10 Correct 980 ms 132088 KB Output is correct
11 Correct 978 ms 132064 KB Output is correct
12 Correct 1008 ms 132728 KB Output is correct
13 Correct 1010 ms 134008 KB Output is correct
14 Correct 990 ms 132088 KB Output is correct
15 Correct 975 ms 130952 KB Output is correct
16 Correct 5 ms 384 KB Output is correct
17 Correct 5 ms 384 KB Output is correct
18 Correct 5 ms 416 KB Output is correct
19 Correct 5 ms 384 KB Output is correct
20 Correct 5 ms 384 KB Output is correct
21 Correct 5 ms 384 KB Output is correct
22 Correct 5 ms 384 KB Output is correct
23 Correct 5 ms 384 KB Output is correct
24 Correct 5 ms 384 KB Output is correct
25 Incorrect 5 ms 384 KB Output isn't correct
26 Halted 0 ms 0 KB -