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*/
#include <iostream>
#include <complex>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
#include <random>
using namespace std;
template<typename T1, typename T2>inline void chkmin(T1 &x, T2 y) { x = (x > y ? y: x);}
template<typename T1, typename T2>inline void chkmax(T1 &x, T2 y) { x = (x < y ? y: x);}
#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define left left224
#define right right224
#define next next224
#define rank rank224
#define prev prev224
#define y1 y1224
#define read(FILENAME) freopen((FILENAME + ".in").c_str(), "r", stdin)
#define write(FILENAME) freopen((FILENAME + ".out").c_str(), "w", stdout)
#define files(FILENAME) read(FILENAME), write(FILENAME)
#define pb push_back
#define mp make_pair
const string FILENAME = "input";
const int MAXN = 100228;
struct point
{
int x, y;
int id;
point(){}
point(int _x, int _y) {
x = _x;
y = _y;
}
};
bool good[MAXN];
point operator +(const point &a, const point &b) {
return point(a.x + b.x, a.y + b.y);
}
point operator -(const point &a, const point &b) {
return point(a.x - b.x, a.y - b.y);
}
long long dist(const point &a, const point &b) {
return 1LL * (a.x - b.x) * (a.x - b.x) + 1LL * (a.y - b.y) * (a.y - b.y);
}
long long vec(const point &a, const point &b) {
return a.x * b.y - a.y * b.x;
}
int n;
point p[MAXN], q[MAXN];
point g;
bool comp(const point &a, const point &b) {
long long s = vec(a - g, b - g);
if (s == 0) {
return dist(a, g) < dist(b, g);
}
return s > 0;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
//read(FILENAME);
cin >> n;
for (int i = 0; i < n; i++) {
cin >> p[i].x >> p[i].y;
p[i].id = i + 1;
}
g = point(1e9, 1e9);
for (int i = 0; i < n; i++) {
if (g.y > p[i].y) {
g = p[i];
} else if (g.y == p[i].y) {
if (g.x > p[i].x) {
g = p[i];
}
}
}
sort(p, p + n, comp);
int m = n;
vector<int> st;
for (int i = 0; i < n; i++) {
if (sz(st) < 2) {
st.pb(i);
} else {
while (sz(st) >= 2 && vec(p[st.back()] - p[st[sz(st) - 2]], p[i] - p[st[sz(st) - 2]]) <= 0) {
st.pop_back();
}
st.pb(i);
}
}
while (sz(st) >= 2 && vec(p[st.back()] - p[st[sz(st) - 2]], p[0] - p[st[sz(st) - 2]]) <= 0) {
st.pop_back();
}
for (int i = 0; i < sz(st); i++) {
q[i] = p[st[i]];
}
n = sz(st);
int uk = 0;
int uk1 = 0;
good[q[uk].id] = true;
int cnt = 0;
while (vec(q[uk], q[(uk + 1) % n]) < 0) {
uk++;
uk %= n;
good[q[uk].id] = true;
cnt++;
if (cnt >= n) {
break;
}
}
cnt = 0;
while (vec(q[uk1], q[(uk1 - 1 + n) % n]) > 0) {
uk1 = (uk1 - 1 + n) % n;
good[q[uk1].id] = true;
cnt++;
if (cnt >= n) {
break;
}
}
vector<int> f;
for (int i = 1; i <= m; i++) {
if (good[i]) {
f.pb(i);
}
}
cout << sz(f) << '\n';
for (auto x: f) {
cout << x << ' ';
}
cout << endl;
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
| 2 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
| 3 |
Incorrect |
3 ms |
376 KB |
Output isn't correct |
| 4 |
Incorrect |
4 ms |
376 KB |
Output isn't correct |
| 5 |
Incorrect |
6 ms |
632 KB |
Output isn't correct |
| 6 |
Incorrect |
6 ms |
632 KB |
Output isn't correct |
| 7 |
Incorrect |
9 ms |
888 KB |
Output isn't correct |
| 8 |
Incorrect |
5 ms |
632 KB |
Output isn't correct |
| 9 |
Incorrect |
4 ms |
504 KB |
Output isn't correct |
| 10 |
Incorrect |
6 ms |
636 KB |
Output isn't correct |
| 11 |
Incorrect |
6 ms |
760 KB |
Output isn't correct |
| 12 |
Incorrect |
8 ms |
888 KB |
Output isn't correct |
| 13 |
Incorrect |
14 ms |
1400 KB |
Output isn't correct |
| 14 |
Incorrect |
15 ms |
1272 KB |
Output isn't correct |
| 15 |
Incorrect |
19 ms |
1528 KB |
Output isn't correct |
| 16 |
Incorrect |
37 ms |
2680 KB |
Output isn't correct |
| 17 |
Incorrect |
44 ms |
3064 KB |
Output isn't correct |
| 18 |
Runtime error |
28 ms |
4472 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
| 19 |
Runtime error |
29 ms |
4368 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
| 20 |
Incorrect |
39 ms |
2936 KB |
Output isn't correct |
