oj.uz

Submission #388362

# Submission time Handle Problem Language Result Execution time Memory
388362 2021-04-11T05:43:01 Z abra_stone None (KOI18_footprint) C++14
14 / 100
 1464 ms 169892 KB 
#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#define N 3005
using namespace std;

typedef long long ll;
struct st{
	ll x, y, id;
} o, a[N];
ll n, ans, d1[N][N], d2[N][N], h1[N][N], h2[N][N];
vector<st> lt, rt;

ll ccw(st p, st q, st r) {
	return p.x * q.y + q.x * r.y + r.x * p.y - q.x * p.y - r.x * q.y - p.x * r.y;
}

bool cmp(st p, st q) {return ccw(o, p, q) > 0;}

bool cmpmn(st p, st q) {
	if (p.y != q.y) return p.y < q.y;
	else return p.x < q.x;
}

void print(ll p, ll q, ll r) {
	if (p == 0) {printf("%lld %lld\n", a[p].x, a[p].y); return;}
	if (r == 1) print(q, h1[p][q], 2);
	else print(q, h2[p][q], 1);
	printf("%lld %lld\n", a[p].x, a[p].y);
}

int main()
{
	ll i, j, k;
	cin >> n;
	for (i = 0; i < n; i++) {
		scanf("%lld %lld", &a[i].x, &a[i].y);
	}
	sort(a, a + n, cmpmn);
	o = a[0];
	sort(a + 1, a + n, cmp);
	for (i = 0; i < n; i++) a[i].id = i;

	for (i = 1; i < n; i++) d1[i][0] = 2;
	for (i = 1; i < n; i++) {
		lt.clear(); rt.clear();
		for (j = 0; j < i; j++) rt.push_back(a[j]);
		for (j = i + 1; j < n; j++) lt.push_back(a[j]);
		o = a[i];
		sort(lt.begin(), lt.end(), cmp);
		sort(rt.begin(), rt.end(), cmp);

		ll mx = -1e9, mi = 0;
		ll I = a[i].id;
		for (j = 0, k = 0; j < lt.size(); j++) {
			ll J = lt[j].id;
			for (; k < rt.size(); k++) {
				ll K = rt[k].id;
				if (ccw(rt[k], a[i], lt[j]) <= 0) break;
				if (d1[I][K] + 1 > mx) mx = d1[I][K] + 1, mi = K;
			}
			d2[J][I] = mx;
			h2[J][I] = mi;
		}
		mx = -1e9, mi = 0;
		for (j = (ll)lt.size() - 1, k = (ll)rt.size() - 1; j >= 0; j--) {
			ll J = lt[j].id;
			for (; k >= 0; k--) {
				ll K = rt[k].id;
				if (ccw(rt[k], a[i], lt[j]) >= 0) break;
				if (d2[I][K] + 1 > mx) mx = d2[I][K] + 1, mi = K;
			}
			d1[J][I] = mx;
			h1[J][I] = mi;
		}
	}
	for (i = 0; i < n; i++) for (j = 0; j < i; j++) ans = max(ans, d1[i][j]);
	if (ans <= 3) {cout << '0'; return 0;}
    cout << ans << endl;
    for (i = 0; i < n; i++) for (j = 0; j < i; j++) if (d1[i][j] == ans) {print(i, j, 1); return 0;}
    return 0;
}

Compilation message

footprint.cpp: In function 'int main()':
footprint.cpp:56:24: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<st>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   for (j = 0, k = 0; j < lt.size(); j++) {
      |                      ~~^~~~~~~~~~~
footprint.cpp:58:13: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<st>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |    for (; k < rt.size(); k++) {
      |           ~~^~~~~~~~~~~
footprint.cpp:38:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   38 |   scanf("%lld %lld", &a[i].x, &a[i].y);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1371 ms 160572 KB Output is correct
2 Correct 1428 ms 165516 KB Output is correct
3 Correct 1408 ms 162924 KB Output is correct
4 Correct 1437 ms 165840 KB Output is correct
5 Correct 1402 ms 164072 KB Output is correct
6 Correct 1433 ms 165752 KB Output is correct
7 Correct 1434 ms 164660 KB Output is correct
8 Correct 1428 ms 166200 KB Output is correct
9 Correct 1442 ms 166756 KB Output is correct
10 Correct 1442 ms 166128 KB Output is correct
11 Correct 1441 ms 165908 KB Output is correct
12 Correct 1447 ms 167060 KB Output is correct
13 Correct 1464 ms 169892 KB Output is correct
14 Correct 1453 ms 165916 KB Output is correct
15 Correct 1412 ms 163388 KB Output is correct

Subtask #2
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 332 KB Output is correct
6 Correct 1 ms 332 KB Output is correct
7 Incorrect 1 ms 332 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 332 KB Output is correct
6 Correct 1 ms 332 KB Output is correct
7 Incorrect 1 ms 332 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #4
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 1371 ms 160572 KB Output is correct
2 Correct 1428 ms 165516 KB Output is correct
3 Correct 1408 ms 162924 KB Output is correct
4 Correct 1437 ms 165840 KB Output is correct
5 Correct 1402 ms 164072 KB Output is correct
6 Correct 1433 ms 165752 KB Output is correct
7 Correct 1434 ms 164660 KB Output is correct
8 Correct 1428 ms 166200 KB Output is correct
9 Correct 1442 ms 166756 KB Output is correct
10 Correct 1442 ms 166128 KB Output is correct
11 Correct 1441 ms 165908 KB Output is correct
12 Correct 1447 ms 167060 KB Output is correct
13 Correct 1464 ms 169892 KB Output is correct
14 Correct 1453 ms 165916 KB Output is correct
15 Correct 1412 ms 163388 KB Output is correct
16 Correct 1 ms 332 KB Output is correct
17 Correct 1 ms 332 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 1 ms 460 KB Output is correct
20 Correct 1 ms 332 KB Output is correct
21 Correct 1 ms 332 KB Output is correct
22 Incorrect 1 ms 332 KB Output isn't correct
23 Halted 0 ms 0 KB -