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Submission #284842

# Submission time Handle Problem Language Result Execution time Memory
284842 2020-08-28T06:45:30 Z youngyojun None (KOI18_footprint) C++17
100 / 100
 1355 ms 110968 KB 
#include <bits/stdc++.h>
#define eb emplace_back
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
ll operator * (const pll &a, const pll &b) { return a.fi * b.se - b.fi * a.se; }
ll ccw(const pll &a, const pll &b, const pll &c) { return a*b + b*c + c*a; }

int D[3005][3005], RD[3005][3005];
int E[3005][3005], RE[3005][3005];

int NV[3005], NVn;
int PV[3005], PVn;

pll P[3005];

int N;

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);

	cin >> N;
	for(int i = 0; i < N; i++) {
		cin >> P[i].fi >> P[i].se;
		if(P[i].se < P[0].se) swap(P[0], P[i]);
	}
	N--;
	sort(P+1, P+N+1, [&](const pll &a, const pll &b) { return ccw(P[0], a, b) > 0; });

	for(int i = 1; i <= N; i++) {
		D[i][0] = 2;

		NVn = PVn = 0;
	{
		int k = i+1;
		for(; k <= N && !ccw(P[0], P[i], P[k]); k++);
		for(; k <= N; k++) NV[NVn++] = k;
	}
	{
		PV[PVn++] = 0;
		int j = i-1;
		for(; j && !ccw(P[0], P[i], P[j]); j--);
		for(; j; j--) PV[PVn++] = j;
	}
		sort(NV, NV+NVn, [&](int a, int b) { return ccw(P[i], P[a], P[b]) > 0; });
		sort(PV, PV+PVn, [&](int a, int b) { return ccw(P[i], P[a], P[b]) > 0; });

		for(int ki = 0, k, ji = 0, j, mx = 0, mxj; ki < NVn; ki++) {
			k = NV[ki];
			for(; ji < PVn; ji++) {
				j = PV[ji];
				if(ccw(P[j], P[i], P[k]) <= 0) break;
				if(mx < D[i][j]) {
					mx = D[i][j];
					mxj = j;
				}
			}
			if(mx) {
				E[k][i] = mx + 1;
				RE[k][i] = mxj;
			}
		}

		for(int ki = NVn-1, k, ji = PVn-1, j, mx = 0, mxj; 0 <= ki; ki--) {
			k = NV[ki];
			for(; 0 <= ji; ji--) {
				j = PV[ji];
				if(ccw(P[j], P[i], P[k]) >= 0) break;
				if(mx < E[i][j]) {
					mx = E[i][j];
					mxj = j;
				}
			}
			if(mx) {
				D[k][i] = mx + 1;
				RD[k][i] = mxj;
			}
		}
	}

{
	int Ans = 0, I, J;
	for(int i = N; i; i--) for(int j = i-1; j; j--)
		if(Ans < D[i][j]) {
			Ans = D[i][j];
			I = i; J = j;
		}
	
	if(Ans < 4) { puts("0"); exit(0); }
	cout << Ans << '\n';

	vector<int> V;
	for(int t = 0; 2 < Ans; Ans--, t ^= 1) {
		V.eb(I);
		I = (t ? RE : RD)[I][J];
		swap(I, J);
	}
	V.eb(I); V.eb(J);

	reverse(V.begin(), V.end());
	for(int v : V) cout << P[v].fi << ' ' << P[v].se << '\n';
}
	return 0;
}

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1066 ms 98524 KB Output is correct
2 Correct 1138 ms 100932 KB Output is correct
3 Correct 1113 ms 99704 KB Output is correct
4 Correct 1123 ms 100984 KB Output is correct
5 Correct 1110 ms 100000 KB Output is correct
6 Correct 1172 ms 101112 KB Output is correct
7 Correct 1131 ms 100480 KB Output is correct
8 Correct 1123 ms 101256 KB Output is correct
9 Correct 1127 ms 101412 KB Output is correct
10 Correct 1115 ms 101276 KB Output is correct
11 Correct 1126 ms 101248 KB Output is correct
12 Correct 1150 ms 101752 KB Output is correct
13 Correct 1149 ms 103024 KB Output is correct
14 Correct 1129 ms 101240 KB Output is correct
15 Correct 1092 ms 99960 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 1 ms 512 KB Output is correct
13 Correct 0 ms 512 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 512 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 512 KB Output is correct
20 Correct 1 ms 512 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 1 ms 512 KB Output is correct
13 Correct 0 ms 512 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 512 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 512 KB Output is correct
20 Correct 1 ms 512 KB Output is correct
21 Correct 11 ms 5408 KB Output is correct
22 Correct 11 ms 5504 KB Output is correct
23 Correct 10 ms 5376 KB Output is correct
24 Correct 12 ms 5888 KB Output is correct
25 Correct 12 ms 5888 KB Output is correct
26 Correct 11 ms 5888 KB Output is correct
27 Correct 11 ms 5760 KB Output is correct
28 Correct 11 ms 5760 KB Output is correct
29 Correct 11 ms 5760 KB Output is correct
30 Correct 11 ms 5888 KB Output is correct
31 Correct 12 ms 5888 KB Output is correct
32 Correct 12 ms 5888 KB Output is correct
33 Correct 6 ms 4352 KB Output is correct
34 Correct 6 ms 4352 KB Output is correct
35 Correct 6 ms 4352 KB Output is correct

Subtask #4
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 1066 ms 98524 KB Output is correct
2 Correct 1138 ms 100932 KB Output is correct
3 Correct 1113 ms 99704 KB Output is correct
4 Correct 1123 ms 100984 KB Output is correct
5 Correct 1110 ms 100000 KB Output is correct
6 Correct 1172 ms 101112 KB Output is correct
7 Correct 1131 ms 100480 KB Output is correct
8 Correct 1123 ms 101256 KB Output is correct
9 Correct 1127 ms 101412 KB Output is correct
10 Correct 1115 ms 101276 KB Output is correct
11 Correct 1126 ms 101248 KB Output is correct
12 Correct 1150 ms 101752 KB Output is correct
13 Correct 1149 ms 103024 KB Output is correct
14 Correct 1129 ms 101240 KB Output is correct
15 Correct 1092 ms 99960 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 512 KB Output is correct
20 Correct 1 ms 512 KB Output is correct
21 Correct 1 ms 512 KB Output is correct
22 Correct 1 ms 384 KB Output is correct
23 Correct 1 ms 512 KB Output is correct
24 Correct 1 ms 384 KB Output is correct
25 Correct 1 ms 512 KB Output is correct
26 Correct 1 ms 512 KB Output is correct
27 Correct 1 ms 512 KB Output is correct
28 Correct 0 ms 512 KB Output is correct
29 Correct 1 ms 384 KB Output is correct
30 Correct 1 ms 512 KB Output is correct
31 Correct 1 ms 384 KB Output is correct
32 Correct 1 ms 384 KB Output is correct
33 Correct 1 ms 384 KB Output is correct
34 Correct 1 ms 512 KB Output is correct
35 Correct 1 ms 512 KB Output is correct
36 Correct 11 ms 5408 KB Output is correct
37 Correct 11 ms 5504 KB Output is correct
38 Correct 10 ms 5376 KB Output is correct
39 Correct 12 ms 5888 KB Output is correct
40 Correct 12 ms 5888 KB Output is correct
41 Correct 11 ms 5888 KB Output is correct
42 Correct 11 ms 5760 KB Output is correct
43 Correct 11 ms 5760 KB Output is correct
44 Correct 11 ms 5760 KB Output is correct
45 Correct 11 ms 5888 KB Output is correct
46 Correct 12 ms 5888 KB Output is correct
47 Correct 12 ms 5888 KB Output is correct
48 Correct 6 ms 4352 KB Output is correct
49 Correct 6 ms 4352 KB Output is correct
50 Correct 6 ms 4352 KB Output is correct
51 Correct 1106 ms 100756 KB Output is correct
52 Correct 1112 ms 101240 KB Output is correct
53 Correct 1145 ms 102828 KB Output is correct
54 Correct 1313 ms 110936 KB Output is correct
55 Correct 1305 ms 110968 KB Output is correct
56 Correct 1355 ms 110860 KB Output is correct
57 Correct 1323 ms 110712 KB Output is correct
58 Correct 1308 ms 110840 KB Output is correct
59 Correct 1344 ms 110944 KB Output is correct
60 Correct 1312 ms 110968 KB Output is correct
61 Correct 1306 ms 110856 KB Output is correct
62 Correct 1306 ms 110960 KB Output is correct
63 Correct 593 ms 67772 KB Output is correct
64 Correct 595 ms 67832 KB Output is correct
65 Correct 603 ms 67864 KB Output is correct
66 Correct 952 ms 110840 KB Output is correct
67 Correct 968 ms 110864 KB Output is correct
68 Correct 983 ms 110840 KB Output is correct