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답안 #242195

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
242195 2020-06-27T05:27:41 Z arnold518 공룡 발자국 (KOI18_footprint) C++14
100 / 100
 1254 ms 142072 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

# 결과 실행 시간 메모리 Grader output
1 Correct 957 ms 129412 KB Output is correct
2 Correct 985 ms 131836 KB Output is correct
3 Correct 966 ms 130552 KB Output is correct
4 Correct 982 ms 132004 KB Output is correct
5 Correct 982 ms 131064 KB Output is correct
6 Correct 998 ms 131960 KB Output is correct
7 Correct 987 ms 131448 KB Output is correct
8 Correct 988 ms 132260 KB Output is correct
9 Correct 986 ms 132488 KB Output is correct
10 Correct 990 ms 132088 KB Output is correct
11 Correct 993 ms 132092 KB Output is correct
12 Correct 999 ms 132676 KB Output is correct
13 Correct 1028 ms 134136 KB Output is correct
14 Correct 979 ms 131964 KB Output is correct
15 Correct 985 ms 130808 KB Output is correct

Subtask #2
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 4 ms 384 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 4 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 4 ms 384 KB Output is correct
9 Correct 5 ms 384 KB Output is correct
10 Correct 5 ms 384 KB Output is correct
11 Correct 5 ms 380 KB Output is correct
12 Correct 5 ms 384 KB Output is correct
13 Correct 4 ms 384 KB Output is correct
14 Correct 5 ms 384 KB Output is correct
15 Correct 5 ms 384 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 384 KB Output is correct
19 Correct 6 ms 384 KB Output is correct
20 Correct 5 ms 384 KB Output is correct

Subtask #3
29.0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 4 ms 384 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 4 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 4 ms 384 KB Output is correct
9 Correct 5 ms 384 KB Output is correct
10 Correct 5 ms 384 KB Output is correct
11 Correct 5 ms 380 KB Output is correct
12 Correct 5 ms 384 KB Output is correct
13 Correct 4 ms 384 KB Output is correct
14 Correct 5 ms 384 KB Output is correct
15 Correct 5 ms 384 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 384 KB Output is correct
19 Correct 6 ms 384 KB Output is correct
20 Correct 5 ms 384 KB Output is correct
21 Correct 12 ms 3840 KB Output is correct
22 Correct 14 ms 3840 KB Output is correct
23 Correct 13 ms 3840 KB Output is correct
24 Correct 15 ms 4224 KB Output is correct
25 Correct 14 ms 4224 KB Output is correct
26 Correct 14 ms 4096 KB Output is correct
27 Correct 14 ms 4096 KB Output is correct
28 Correct 14 ms 4096 KB Output is correct
29 Correct 14 ms 4096 KB Output is correct
30 Correct 14 ms 4096 KB Output is correct
31 Correct 15 ms 4352 KB Output is correct
32 Correct 19 ms 4224 KB Output is correct
33 Correct 11 ms 4224 KB Output is correct
34 Correct 13 ms 4224 KB Output is correct
35 Correct 10 ms 4096 KB Output is correct

Subtask #4
45.0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 957 ms 129412 KB Output is correct
2 Correct 985 ms 131836 KB Output is correct
3 Correct 966 ms 130552 KB Output is correct
4 Correct 982 ms 132004 KB Output is correct
5 Correct 982 ms 131064 KB Output is correct
6 Correct 998 ms 131960 KB Output is correct
7 Correct 987 ms 131448 KB Output is correct
8 Correct 988 ms 132260 KB Output is correct
9 Correct 986 ms 132488 KB Output is correct
10 Correct 990 ms 132088 KB Output is correct
11 Correct 993 ms 132092 KB Output is correct
12 Correct 999 ms 132676 KB Output is correct
13 Correct 1028 ms 134136 KB Output is correct
14 Correct 979 ms 131964 KB Output is correct
15 Correct 985 ms 130808 KB Output is correct
16 Correct 5 ms 384 KB Output is correct
17 Correct 4 ms 384 KB Output is correct
18 Correct 4 ms 384 KB Output is correct
19 Correct 4 ms 384 KB Output is correct
20 Correct 5 ms 384 KB Output is correct
21 Correct 4 ms 384 KB Output is correct
22 Correct 5 ms 384 KB Output is correct
23 Correct 4 ms 384 KB Output is correct
24 Correct 5 ms 384 KB Output is correct
25 Correct 5 ms 384 KB Output is correct
26 Correct 5 ms 380 KB Output is correct
27 Correct 5 ms 384 KB Output is correct
28 Correct 4 ms 384 KB Output is correct
29 Correct 5 ms 384 KB Output is correct
30 Correct 5 ms 384 KB Output is correct
31 Correct 5 ms 384 KB Output is correct
32 Correct 5 ms 384 KB Output is correct
33 Correct 5 ms 384 KB Output is correct
34 Correct 6 ms 384 KB Output is correct
35 Correct 5 ms 384 KB Output is correct
36 Correct 12 ms 3840 KB Output is correct
37 Correct 14 ms 3840 KB Output is correct
38 Correct 13 ms 3840 KB Output is correct
39 Correct 15 ms 4224 KB Output is correct
40 Correct 14 ms 4224 KB Output is correct
41 Correct 14 ms 4096 KB Output is correct
42 Correct 14 ms 4096 KB Output is correct
43 Correct 14 ms 4096 KB Output is correct
44 Correct 14 ms 4096 KB Output is correct
45 Correct 14 ms 4096 KB Output is correct
46 Correct 15 ms 4352 KB Output is correct
47 Correct 19 ms 4224 KB Output is correct
48 Correct 11 ms 4224 KB Output is correct
49 Correct 13 ms 4224 KB Output is correct
50 Correct 10 ms 4096 KB Output is correct
51 Correct 1025 ms 131784 KB Output is correct
52 Correct 1033 ms 132076 KB Output is correct
53 Correct 1068 ms 133728 KB Output is correct
54 Correct 1195 ms 141952 KB Output is correct
55 Correct 1203 ms 141824 KB Output is correct
56 Correct 1196 ms 141904 KB Output is correct
57 Correct 1203 ms 141852 KB Output is correct
58 Correct 1192 ms 141696 KB Output is correct
59 Correct 1187 ms 141820 KB Output is correct
60 Correct 1254 ms 141944 KB Output is correct
61 Correct 1157 ms 141816 KB Output is correct
62 Correct 1159 ms 142072 KB Output is correct
63 Correct 593 ms 141796 KB Output is correct
64 Correct 601 ms 141836 KB Output is correct
65 Correct 610 ms 141920 KB Output is correct
66 Correct 796 ms 141820 KB Output is correct
67 Correct 795 ms 141672 KB Output is correct
68 Correct 836 ms 141816 KB Output is correct