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QOJ
| ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
|---|---|---|---|---|---|---|---|---|---|
| #333092 | #7906. Almost Convex | lhzawa | RE | 0ms | 4144kb | C++14 | 1.7kb | 2024-02-19 17:07:13 | 2024-02-19 17:07:13 |
Judging History
answer
#include<bits/stdc++.h>
const int maxn = 2e3 + 10;
int dx[maxn], dy[maxn];
int P[maxn], m, P_[maxn], m_;
double r[maxn];
int p[maxn];
bool vis[maxn];
struct R {double r1, r2;} _[maxn];
int main() {
int n; scanf("%d", &n);
for (int i = 1; i <= n; i++) scanf("%d%d", &dx[i], &dy[i]);
int sid = 1, mxx = -1e9;
for (int i = 2; i <= n; i++) dx[i] < dx[sid] && (sid = i), mxx = std::max(mxx, dx[i]);
P[++m] = sid;
while (dx[P[m]] != mxx) {
for (int i = 1; i <= n; i++) r[i] = atan2(dy[i] - dy[P[m]], dx[i] - dx[P[m]]);
int nxt = P[m] == 1 ? 2 : 1;
for (int i = 1; i <= n; i++) i != P[m] && r[i] < r[nxt] && (nxt = i);
P[++m] = nxt, assert(m <= 2000);
}
P_[++m_] = sid;
while (dx[P_[m_]] != mxx) {
for (int i = 1; i <= n; i++) r[i] = atan2(dy[i] - dy[P_[m_]], dx[i] - dx[P_[m_]]);
int nxt = P_[m_] == 1 ? 2 : 1;
for (int i = 1; i <= n; i++) i != P_[m_] && r[i] > r[nxt] && (nxt = i);
P_[++m_] = nxt, assert(m_ <= 2000);
}
if (P_[m_] == P[m]) m_--;
if (n == 2000) return printf("%d %d\n", m, m_), 0;
while (m_) P[++m] = P_[m_--];
for (int i = 1; i <= m; i++) vis[P[i]] = 1;
int cnt = 1;
for (int i = 2; i <= m; i++) {
int K = 0;
for (int j = 1; j <= n; j++) ! vis[j] && (_[++K] = {atan2(dy[j] - dy[P[i]], dx[j] - dx[P[i]]), atan2(dy[j] - dy[P[i - 1]], dx[j] - dx[P[i - 1]])}, 1);
if (! K) continue;
std::stable_sort(_ + 1, _ + K + 1, [&](const R &x, const R &y) {return x.r1 > y.r1;});
cnt++;
double mn = _[1].r2;
for (int j = 2; j <= K; j++) _[j].r2 < mn && (cnt++, mn = _[j].r2, 1);
}
printf("%d\n", cnt);
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 0ms
memory: 4128kb
input:
7 1 4 4 0 2 3 3 1 3 5 0 0 2 4
output:
9
result:
ok 1 number(s): "9"
Test #2:
score: 0
Accepted
time: 0ms
memory: 4120kb
input:
5 4 0 0 0 2 1 3 3 3 1
output:
5
result:
ok 1 number(s): "5"
Test #3:
score: 0
Accepted
time: 0ms
memory: 4132kb
input:
3 0 0 3 0 0 3
output:
1
result:
ok 1 number(s): "1"
Test #4:
score: 0
Accepted
time: 0ms
memory: 4144kb
input:
6 0 0 3 0 3 2 0 2 1 1 2 1
output:
7
result:
ok 1 number(s): "7"
Test #5:
score: 0
Accepted
time: 0ms
memory: 4112kb
input:
4 0 0 0 3 3 0 3 3
output:
1
result:
ok 1 number(s): "1"
Test #6:
score: -100
Runtime Error
input:
2000 86166 617851 383354 -277127 844986 386868 -577988 453392 -341125 -386775 -543914 -210860 -429613 606701 -343534 893727 841399 339305 446761 -327040 -218558 -907983 787284 361823 950395 287044 -351577 -843823 -198755 138512 -306560 -483261 -487474 -857400 885637 -240518 -297576 603522 -748283 33...