oj.uz

Submission #63153

# Submission time Handle Problem Language Result Execution time Memory
63153 2018-08-01T01:19:19 Z khsoo01 None (KOI18_footprint) C++11
100 / 100
 1911 ms 84672 KB 
#include<bits/stdc++.h>
#define X first
#define Y second
using namespace std;
typedef pair<int,int> pii;

const int N = 3005, inf = 1e9;

int n;
pii a[N], dt[N][N][2], piv;

vector<int> ans;

long long ccw (pii &A, pii &B, pii &C) {
	return (1ll*A.X*B.Y+1ll*B.X*C.Y+1ll*C.X*A.Y) - (1ll*A.Y*B.X+1ll*B.Y*C.X+1ll*C.Y*A.X);
}

bool cmp (pii &A, pii &B) {
	return ccw(piv, A, B) > 0;
}

bool cmp2 (int A, int B) {
	return ccw(piv, a[A], a[B]) > 0;
}

int main()
{
	scanf("%d",&n);
	for(int i=1;i<=n;i++) {
		scanf("%d%d",&a[i].X,&a[i].Y);
		if(a[i].Y < a[1].Y) swap(a[i], a[1]);
	}
	piv = a[1];
	sort(a+2, a+1+n, cmp);
	for(int i=1;i<=n;i++) {
		dt[1][i][0] = {1, 0};
	}
	for(int k=2;k<=n;k++) {
		vector<int> A, B;
		A.push_back(1);
		for(int i=2;i<k;i++) {
			if(ccw(a[1], a[k], a[i]) != 0) A.push_back(i);
		}
		for(int i=k+1;i<=n;i++) {
			if(ccw(a[1], a[k], a[i]) != 0) B.push_back(i);
		}
		piv = a[k];
		sort(A.begin(), A.end(), cmp2);
		sort(B.begin(), B.end(), cmp2);
		int j = 0;
		pii V = {-inf, -inf};
		for(int i=0;i<=(int)A.size();i++) {
			int T = (i < (int)A.size() ? A[i] : k);
			while(j<(int)B.size() && ccw(a[T], a[k], a[B[j]]) <= 0) {
				dt[k][B[j]][1] = max(dt[k][B[j]][1], V);
				j++;
			}
			V = max(V, {dt[T][k][0].X+1, T});
		}
		j = (int)B.size()-1;
		V = {-inf, -inf};
		for(int i=(int)A.size()-1;i>=-1;i--) {
			int T = (i >= 0 ? A[i] : k);
			while(j >= 0 && ccw(a[T], a[k], a[B[j]]) >= 0) {
				dt[k][B[j]][0] = max(dt[k][B[j]][0], V);
				j--;
			}
			V = max(V, {dt[T][k][1].X+1, T});
		}
	}
	int V = 0, A, B, C = 0;
	for(int i=1;i<=n;i++) {
		for(int j=1;j<=n;j++) {
			if(V < dt[i][j][0].X) {
				V = dt[i][j][0].X;
				A = i;
				B = j;
			}
		}
	}
	if(V == 1) {
		puts("0");
		return 0;
	}
	for(int i=0;i<V;i++) {
		ans.push_back(B);
		int T = A;
		A = dt[A][B][C].Y;
		B = T;
		C ^= 1;
	}
	ans.push_back(1);
	reverse(ans.begin(), ans.end());
	printf("%d\n",(int)ans.size());
	for(auto &T : ans) {
		printf("%d %d\n", a[T].X, a[T].Y);
	}
}

Compilation message

footprint.cpp: In function 'int main()':
footprint.cpp:28:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
footprint.cpp:30:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&a[i].X,&a[i].Y);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
footprint.cpp:88:5: warning: 'A' may be used uninitialized in this function [-Wmaybe-uninitialized]
   A = dt[A][B][C].Y;
     ^

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1393 ms 70052 KB Output is correct
2 Correct 1426 ms 72624 KB Output is correct
3 Correct 1449 ms 72624 KB Output is correct
4 Correct 1346 ms 72888 KB Output is correct
5 Correct 1393 ms 72888 KB Output is correct
6 Correct 1487 ms 73168 KB Output is correct
7 Correct 1402 ms 73168 KB Output is correct
8 Correct 1406 ms 73484 KB Output is correct
9 Correct 1496 ms 73716 KB Output is correct
10 Correct 1544 ms 73716 KB Output is correct
11 Correct 1442 ms 73716 KB Output is correct
12 Correct 1603 ms 74140 KB Output is correct
13 Correct 1504 ms 75540 KB Output is correct
14 Correct 1550 ms 75540 KB Output is correct
15 Correct 1444 ms 75540 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 75540 KB Output is correct
2 Correct 2 ms 75540 KB Output is correct
3 Correct 2 ms 75540 KB Output is correct
4 Correct 3 ms 75540 KB Output is correct
5 Correct 2 ms 75540 KB Output is correct
6 Correct 3 ms 75540 KB Output is correct
7 Correct 3 ms 75540 KB Output is correct
8 Correct 3 ms 75540 KB Output is correct
9 Correct 2 ms 75540 KB Output is correct
10 Correct 2 ms 75540 KB Output is correct
11 Correct 4 ms 75540 KB Output is correct
12 Correct 3 ms 75540 KB Output is correct
13 Correct 3 ms 75540 KB Output is correct
14 Correct 2 ms 75540 KB Output is correct
15 Correct 3 ms 75540 KB Output is correct
16 Correct 3 ms 75540 KB Output is correct
17 Correct 2 ms 75540 KB Output is correct
18 Correct 3 ms 75540 KB Output is correct
19 Correct 2 ms 75540 KB Output is correct
20 Correct 3 ms 75540 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 75540 KB Output is correct
2 Correct 2 ms 75540 KB Output is correct
3 Correct 2 ms 75540 KB Output is correct
4 Correct 3 ms 75540 KB Output is correct
5 Correct 2 ms 75540 KB Output is correct
6 Correct 3 ms 75540 KB Output is correct
7 Correct 3 ms 75540 KB Output is correct
8 Correct 3 ms 75540 KB Output is correct
9 Correct 2 ms 75540 KB Output is correct
10 Correct 2 ms 75540 KB Output is correct
11 Correct 4 ms 75540 KB Output is correct
12 Correct 3 ms 75540 KB Output is correct
13 Correct 3 ms 75540 KB Output is correct
14 Correct 2 ms 75540 KB Output is correct
15 Correct 3 ms 75540 KB Output is correct
16 Correct 3 ms 75540 KB Output is correct
17 Correct 2 ms 75540 KB Output is correct
18 Correct 3 ms 75540 KB Output is correct
19 Correct 2 ms 75540 KB Output is correct
20 Correct 3 ms 75540 KB Output is correct
21 Correct 20 ms 75540 KB Output is correct
22 Correct 15 ms 75540 KB Output is correct
23 Correct 15 ms 75540 KB Output is correct
24 Correct 23 ms 75540 KB Output is correct
25 Correct 18 ms 75540 KB Output is correct
26 Correct 17 ms 75540 KB Output is correct
27 Correct 17 ms 75540 KB Output is correct
28 Correct 17 ms 75540 KB Output is correct
29 Correct 16 ms 75540 KB Output is correct
30 Correct 18 ms 75540 KB Output is correct
31 Correct 21 ms 75540 KB Output is correct
32 Correct 21 ms 75540 KB Output is correct
33 Correct 12 ms 75540 KB Output is correct
34 Correct 13 ms 75540 KB Output is correct
35 Correct 15 ms 75540 KB Output is correct

Subtask #4
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 1393 ms 70052 KB Output is correct
2 Correct 1426 ms 72624 KB Output is correct
3 Correct 1449 ms 72624 KB Output is correct
4 Correct 1346 ms 72888 KB Output is correct
5 Correct 1393 ms 72888 KB Output is correct
6 Correct 1487 ms 73168 KB Output is correct
7 Correct 1402 ms 73168 KB Output is correct
8 Correct 1406 ms 73484 KB Output is correct
9 Correct 1496 ms 73716 KB Output is correct
10 Correct 1544 ms 73716 KB Output is correct
11 Correct 1442 ms 73716 KB Output is correct
12 Correct 1603 ms 74140 KB Output is correct
13 Correct 1504 ms 75540 KB Output is correct
14 Correct 1550 ms 75540 KB Output is correct
15 Correct 1444 ms 75540 KB Output is correct
16 Correct 2 ms 75540 KB Output is correct
17 Correct 2 ms 75540 KB Output is correct
18 Correct 2 ms 75540 KB Output is correct
19 Correct 3 ms 75540 KB Output is correct
20 Correct 2 ms 75540 KB Output is correct
21 Correct 3 ms 75540 KB Output is correct
22 Correct 3 ms 75540 KB Output is correct
23 Correct 3 ms 75540 KB Output is correct
24 Correct 2 ms 75540 KB Output is correct
25 Correct 2 ms 75540 KB Output is correct
26 Correct 4 ms 75540 KB Output is correct
27 Correct 3 ms 75540 KB Output is correct
28 Correct 3 ms 75540 KB Output is correct
29 Correct 2 ms 75540 KB Output is correct
30 Correct 3 ms 75540 KB Output is correct
31 Correct 3 ms 75540 KB Output is correct
32 Correct 2 ms 75540 KB Output is correct
33 Correct 3 ms 75540 KB Output is correct
34 Correct 2 ms 75540 KB Output is correct
35 Correct 3 ms 75540 KB Output is correct
36 Correct 20 ms 75540 KB Output is correct
37 Correct 15 ms 75540 KB Output is correct
38 Correct 15 ms 75540 KB Output is correct
39 Correct 23 ms 75540 KB Output is correct
40 Correct 18 ms 75540 KB Output is correct
41 Correct 17 ms 75540 KB Output is correct
42 Correct 17 ms 75540 KB Output is correct
43 Correct 17 ms 75540 KB Output is correct
44 Correct 16 ms 75540 KB Output is correct
45 Correct 18 ms 75540 KB Output is correct
46 Correct 21 ms 75540 KB Output is correct
47 Correct 21 ms 75540 KB Output is correct
48 Correct 12 ms 75540 KB Output is correct
49 Correct 13 ms 75540 KB Output is correct
50 Correct 15 ms 75540 KB Output is correct
51 Correct 1470 ms 75540 KB Output is correct
52 Correct 1521 ms 75540 KB Output is correct
53 Correct 1584 ms 75956 KB Output is correct
54 Correct 1697 ms 84252 KB Output is correct
55 Correct 1761 ms 84252 KB Output is correct
56 Correct 1911 ms 84340 KB Output is correct
57 Correct 1851 ms 84340 KB Output is correct
58 Correct 1775 ms 84340 KB Output is correct
59 Correct 1820 ms 84356 KB Output is correct
60 Correct 1875 ms 84592 KB Output is correct
61 Correct 1778 ms 84592 KB Output is correct
62 Correct 1812 ms 84652 KB Output is correct
63 Correct 1057 ms 84652 KB Output is correct
64 Correct 1189 ms 84652 KB Output is correct
65 Correct 1093 ms 84652 KB Output is correct
66 Correct 1448 ms 84652 KB Output is correct
67 Correct 1417 ms 84652 KB Output is correct
68 Correct 1441 ms 84672 KB Output is correct