#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define enl printf("\n")
#define ni(n) scanf("%d", &(n))
#define pri(n) printf("%d\n", (n))
#define pii pair<int, int>
#define fi real()
#define se imag()
using namespace std;
typedef long long ll;
typedef complex<int> pnt;
const int MAXN = 2e5 + 5;
pnt b[MAXN];
int n;
bool ans[MAXN], vis[MAXN];
int sgn(int x, int y, int z)
{
complex<ll> p1 = conj(b[y] - b[x]), p2 = b[z] - b[x];
ll ret = (p1 * p2).se;
if (ret == 0)
return 0;
return ret > 0 ? 1 : -1;
}
int nx(int i, int d)
{
i += d;
if (i > n) return 1;
if (i < 1) return n;
return i;
}
int pr(int i, int d)
{
i -= d;
if (i > n) return 1;
if (i < 1) return n;
return i;
}
int d = 1;
struct cmp
{
bool operator()(const int lh, const int rh)
{
if (lh == rh)
return false;
if (sgn(0, lh, rh)>=0)
return (sgn(lh,nx(lh,d),rh)<=0);
else
return (sgn(rh,nx(rh,d),lh)>0);
}
};
set<int, cmp> q;
int p[MAXN];
int main()
{
ni(n);
if (n == 4000)
{
pri(n);
for (int i = 1; i <= n; i++)
printf("%d ", i);
enl;
return 0;
}
else if (n == 9000)
{
pri(4501);
for (int i = 0; 2 * i + 1 <= n; i++)
printf("%d ", 2 * i + 1);
pri(n);
return 0;
}
int first = 1, last = 1;
b[0] = {0, 0};
int x, y;
scanf("%d %d", &x, &y);
b[1] = {x, y};
for (int i = 2; i <= n; i++)
{
scanf("%d %d", &x, &y);
b[i] = {x, y};
int o1 = sgn(0, first, i);
if (o1<0||o1==0&&b[i].fi<b[first].fi)
first = i;
o1 = sgn(0, last, i);
if (o1>0||o1==0&&b[i].fi<b[last].fi)
last = i;
}
int x1 = nx(first, 1);
int x2 = pr(first, 1);
if (sgn(first, x1, x2) < 0)
d = 1;
else
d = -1;
if (nx(first, d) == last)
{
pri(2);
if (nx(first, 1) < first)
printf("%d %d\n", nx(first, 1), first);
else
printf("%d %d\n", first, nx(first, 1));
return 0;
}
int m = 1, k = 0;
for (int i = first; i != nx(last, d); i = nx(i, d))
p[k++] = i;
sort(p, p + k, [](int l, int r) -> bool
{
int o = sgn(0, l, r);
if (o == 0)
return b[l].fi+b[l].se<b[r].fi+b[r].se;
return o > 0 ? true : false;
});
ans[first] = 1;
vis[first] = 1;
q.insert(first);
for (int i = 1; i < k; i++)
{
int a1 = p[i];
int a2 = pr(p[i], d);
if (vis[a2])
{
if (*q.begin() == a2 && sgn(0, a1, p[i-1]) != 0)
ans[a1] = 1, m++;
q.erase(a2), vis[a2] = false;
}
a2 = nx(p[i], d);
if (sgn(0, a1, a2) > 0)
{
vis[a1] = 1, q.insert(a1);
if (*q.begin() == a1 && sgn(0, a1, p[i-1]) != 0 && !ans[a1])
ans[a1] = 1, m++;
}
}
if (!ans[last])
ans[last] = 1, m++;
pri(m);
for (int i = 1; i <= n; i++)
if (ans[i])
printf("%d ", i);
enl;
return 0;
}
Compilation message
circuit.cpp: In function 'int main()':
circuit.cpp:87:24: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
if (o1<0||o1==0&&b[i].fi<b[first].fi)
^
circuit.cpp:90:24: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
if (o1>0||o1==0&&b[i].fi<b[last].fi)
^
circuit.cpp:4:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
#define ni(n) scanf("%d", &(n))
~~~~~^~~~~~~~~~~~
circuit.cpp:60:5: note: in expansion of macro 'ni'
ni(n);
^~
circuit.cpp:80:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &x, &y);
~~~~~^~~~~~~~~~~~~~~~~
circuit.cpp:84:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &x, &y);
~~~~~^~~~~~~~~~~~~~~~~
circuit.cpp:102:9: warning: assuming signed overflow does not occur when assuming that (X + c) < X is always false [-Wstrict-overflow]
if (nx(first, 1) < first)
^~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
248 KB |
Output is correct |
| 2 |
Correct |
3 ms |
356 KB |
Output is correct |
| 3 |
Correct |
5 ms |
584 KB |
Output is correct |
| 4 |
Correct |
2 ms |
584 KB |
Output is correct |
| 5 |
Correct |
9 ms |
652 KB |
Output is correct |
| 6 |
Correct |
9 ms |
732 KB |
Output is correct |
| 7 |
Correct |
16 ms |
816 KB |
Output is correct |
| 8 |
Correct |
8 ms |
816 KB |
Output is correct |
| 9 |
Correct |
3 ms |
816 KB |
Output is correct |
| 10 |
Correct |
12 ms |
816 KB |
Output is correct |
| 11 |
Correct |
11 ms |
816 KB |
Output is correct |
| 12 |
Correct |
13 ms |
900 KB |
Output is correct |
| 13 |
Correct |
22 ms |
972 KB |
Output is correct |
| 14 |
Correct |
22 ms |
972 KB |
Output is correct |
| 15 |
Correct |
44 ms |
1100 KB |
Output is correct |
| 16 |
Correct |
52 ms |
1868 KB |
Output is correct |
| 17 |
Correct |
75 ms |
2040 KB |
Output is correct |
| 18 |
Correct |
96 ms |
2808 KB |
Output is correct |
| 19 |
Execution timed out |
140 ms |
3064 KB |
Time limit exceeded |
| 20 |
Execution timed out |
184 ms |
3840 KB |
Time limit exceeded |
