| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 63152 |
2018-08-01T01:15:56 Z |
khsoo01 |
None (KOI18_footprint) |
C++11 |
|
1326 ms |
70000 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;
A = B;
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:87:7: warning: unused variable 'T' [-Wunused-variable]
int T = A;
^
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);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1326 ms |
70000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
70000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
70000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1326 ms |
70000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
