| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 486519 |
2021-11-11T21:50:48 Z |
rainboy |
Relay (COI16_relay) |
C |
|
1 ms |
332 KB |
#include <stdio.h>
#define N 100000
#define M 100000
unsigned int X = 12345;
int rand_() {
return (X *= 3) >> 1;
}
long long cross2(int x1, int y1, int x2, int y2) {
return (long long) x1 * y2 - (long long) x2 * y1;
}
int xx[N + M], yy[N + M], xx_[N * 2], yy_[N * 2], idx[N * 2], n, m;
long long cross(int i, int j, int k) {
return cross2(xx[j] - xx[i], yy[j] - yy[i], xx[k] - xx[i], yy[k] - yy[i]);
}
int compare1(int i, int j) {
return xx[i] != xx[j] ? xx[i] - xx[j] : yy[i] - yy[j];
}
int compare2(int x1, int y1, int x2, int y2) {
int sgn1 = x1 < 0 || x1 == 0 && y1 < 0 ? -1 : 1;
int sgn2 = x2 < 0 || x2 == 0 && y2 < 0 ? -1 : 1;
long long c;
if (sgn1 != sgn2)
return sgn1 - sgn2;
c = cross2(x1, y1, x2, y2);
return c == 0 ? 0 : (c > 0 ? -1 : 1);
}
void sort(int *ii, int l, int r) {
while (l < r) {
int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;
while (j < k) {
int c = compare2(xx_[ii[j]], yy_[ii[j]], xx_[i_], yy_[i_]);
if (c == 0)
j++;
else if (c < 0) {
tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
i++, j++;
} else {
k--;
tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
}
}
sort(ii, l, i);
l = k;
}
}
int intersect(int l1, int r1, int l2, int r2) {
int l1r1 = l1 <= r1, r1l2 = r1 < l2, l2r2 = l2 <= r2, r2l1 = r2 < l1;
return !(l1r1 && r1l2 && l2r2 || r1l2 && l2r2 && r2l1 || l2r2 && r2l1 && l1r1 || r2l1 && l1r1 && r1l2);
}
int l, r;
void find_tangents(int o, int *p, int *q) {
int lower, upper;
if (compare1(o, n + l) < 0) {
lower = -1, upper = (r - l + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (cross(o, n + (l + i) % m, n + (l + i + 1) % m) >= 0)
lower = i;
else
upper = i;
}
*p = (l + upper) % m;
lower = -1, upper = (l - r + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (cross(o, n + (l - i + m) % m, n + (l - (i + 1) + m) % m) <= 0)
lower = i;
else
upper = i;
}
*q = (l - upper + m) % m;
} else if (compare1(o, n + r) > 0) {
lower = -1, upper = (l - r + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (cross(o, n + (r + i) % m, n + (r + i + 1) % m) >= 0)
lower = i;
else
upper = i;
}
*p = (r + upper) % m;
lower = -1, upper = (r - l + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (cross(o, n + (r - i + m) % m, n + (r - (i + 1) + m) % m) <= 0)
lower = i;
else
upper = i;
}
*q = (r - upper + m) % m;
} else if (cross(o, n + l, n + r) > 0) {
lower = -1, upper = (r - l + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (compare1(o, n + (r - i + m) % m) < 0 && cross(o, n + (r - i + m) % m, n + (r - (i + 1) + m) % m) > 0)
lower = i;
else
upper = i;
}
*p = (r - upper + m) % m;
lower = -1, upper = (r - l + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (compare1(o, n + (l + i) % m) > 0 && cross(o, n + (l + i) % m, n + (l + i + 1) % m) < 0)
lower = i;
else
upper = i;
}
*q = (l + upper) % m;
} else {
lower = -1, upper = (l - r + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (compare1(o, n + (l - i + m) % m) < 0 && cross(o, n + (l - i + m) % m, n + (l - (i + 1) + m) % m) > 0)
lower = i;
else
upper = i;
}
*p = (l - upper + m) % m;
lower = -1, upper = (l - r + m) % m;
while (upper - lower > 1) {
int i = (lower + upper) / 2;
if (compare1(o, n + (r + i) % m) > 0 && cross(o, n + (r + i) % m, n + (r + i + 1) % m) < 0)
lower = i;
else
upper = i;
}
*q = (r + upper) % m;
}
}
int main() {
static int ii[N * 2], dd[N * 2 + 1];
int n_, i, j, k;
scanf("%d", &n);
for (i = 0; i < n; i++)
scanf("%d%d", &xx[i], &yy[i]);
scanf("%d", &m);
l = -1, r = -1;
for (j = m - 1; j >= 0; j--) {
scanf("%d%d", &xx[n + j], &yy[n + j]);
if (l == -1 || compare1(n + l, n + j) > 0)
l = j;
if (r == -1 || compare1(n + r, n + j) < 0)
r = j;
}
for (i = 0; i < n; i++) {
int p, q;
find_tangents(i, &p, &q);
xx_[i << 1 | 0] = xx[i] - xx[n + p], yy_[i << 1 | 0] = yy[i] - yy[n + p];
xx_[i << 1 | 1] = xx[n + q] - xx[i], yy_[i << 1 | 1] = yy[n + q] - yy[i];
}
for (i = 0; i < n * 2; i++)
ii[i] = i;
sort(ii, 0, n * 2);
for (i = 0, n_ = 0; i < n * 2; i++)
idx[ii[i]] = i + 1 == n * 2 || compare2(xx_[ii[i + 1]], yy_[ii[i + 1]], xx_[ii[i]], yy_[ii[i]]) != 0 ? n_++ : n_;
for (i = 1; i < n; i++) {
int l = idx[i << 1 | 0], r = idx[i << 1 | 1];
if (intersect(idx[0 << 1 | 0], idx[0 << 1 | 1], l, r)) {
if (l < r)
dd[l]++, dd[r + 1]--;
else
dd[l]++, dd[n_]--, dd[0]++, dd[r + 1]--;
}
}
for (i = 1; i < n_; i++)
dd[i] += dd[i - 1];
for (i = 0; i < n_; i++)
if (dd[i] > 0)
dd[i] = 1;
for (i = 1; i < n_; i++)
dd[i] += dd[i - 1];
k = 0;
for (i = 1; i < n; i++) {
int l = idx[i << 1 | 0], r = idx[i << 1 | 1];
if ((l < r ? dd[r] - (l == 0 ? 0 : dd[l - 1]) : dd[n_ - 1] - dd[l - 1] + dd[r]) > 0)
k++;
}
printf("%d\n", k);
return 0;
}
Compilation message
relay.c: In function 'compare2':
relay.c:27:31: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
27 | int sgn1 = x1 < 0 || x1 == 0 && y1 < 0 ? -1 : 1;
| ~~~~~~~~^~~~~~~~~
relay.c:28:31: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
28 | int sgn2 = x2 < 0 || x2 == 0 && y2 < 0 ? -1 : 1;
| ~~~~~~~~^~~~~~~~~
relay.c: In function 'intersect':
relay.c:62:24: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
62 | return !(l1r1 && r1l2 && l2r2 || r1l2 && l2r2 && r2l1 || l2r2 && r2l1 && l1r1 || r2l1 && l1r1 && r1l2);
| ~~~~~~~~~~~~~^~~~~~~
relay.c:62:72: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
62 | return !(l1r1 && r1l2 && l2r2 || r1l2 && l2r2 && r2l1 || l2r2 && r2l1 && l1r1 || r2l1 && l1r1 && r1l2);
| ~~~~~~~~~~~~~^~~~~~~
relay.c:62:96: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
62 | return !(l1r1 && r1l2 && l2r2 || r1l2 && l2r2 && r2l1 || l2r2 && r2l1 && l1r1 || r2l1 && l1r1 && r1l2);
| ~~~~~~~~~~~~~^~~~~~~
relay.c: In function 'main':
relay.c:161:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
161 | scanf("%d", &n);
| ^~~~~~~~~~~~~~~
relay.c:163:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
163 | scanf("%d%d", &xx[i], &yy[i]);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
relay.c:164:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
164 | scanf("%d", &m);
| ^~~~~~~~~~~~~~~
relay.c:167:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
167 | scanf("%d%d", &xx[n + j], &yy[n + j]);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
