#include <stdio.h>
#define N 1000
long long cross2(int x1, int y1, int x2, int y2) {
return (long long) x1 * y2 - (long long) x2 * y1;
}
long long cross(int x0, int y0, int x1, int y1, int x2, int y2) {
return cross2(x1 - x0, y1 - y0, x2 - x0, y2 - y0);
}
int xx[N], yy[N];
int intersect(int i, int j, int k, int l) {
long long cijk = cross(xx[i], yy[i], xx[j], yy[j], xx[k], yy[k]);
long long cijl = cross(xx[i], yy[i], xx[j], yy[j], xx[l], yy[l]);
long long ckli = cross(xx[k], yy[k], xx[l], yy[l], xx[i], yy[i]);
long long cklj = cross(xx[k], yy[k], xx[l], yy[l], xx[j], yy[j]);
return (cijk > 0) != (cijl > 0) && (ckli > 0) != (cklj > 0);
}
int main() {
static char bad[N][N];
int n, i, j, k, l, ans;
scanf("%d", &n);
for (i = 0; i < n; i++)
scanf("%d%d", &xx[i], &yy[i]);
for (i = 0; i < n; i++)
for (j = i + 1; j < n; j++)
for (k = j + 1; k < n; k++)
for (l = k + 1; l < n; l++) {
if (intersect(i, j, k, l))
bad[i][j] = bad[k][l] = 1;
if (intersect(i, k, j, l))
bad[i][k] = bad[j][l] = 1;
if (intersect(i, l, j, k))
bad[i][l] = bad[j][k] = 1;
}
ans = 0;
for (i = 0; i < n; i++)
for (j = i + 1; j < n; j++)
if (!bad[i][j])
ans++;
printf("%d\n", ans);
return 0;
}
Compilation message
geometrija.c: In function 'main':
geometrija.c:28:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
28 | scanf("%d", &n);
| ^~~~~~~~~~~~~~~
geometrija.c:30:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
30 | scanf("%d%d", &xx[i], &yy[i]);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
204 KB |
Output is correct |
| 2 |
Correct |
3 ms |
204 KB |
Output is correct |
| 3 |
Correct |
3 ms |
204 KB |
Output is correct |
| 4 |
Correct |
2 ms |
204 KB |
Output is correct |
| 5 |
Correct |
2 ms |
204 KB |
Output is correct |
| 6 |
Correct |
2 ms |
204 KB |
Output is correct |
| 7 |
Correct |
3 ms |
204 KB |
Output is correct |
| 8 |
Correct |
3 ms |
320 KB |
Output is correct |
| 9 |
Correct |
2 ms |
204 KB |
Output is correct |
| 10 |
Correct |
3 ms |
204 KB |
Output is correct |
| 11 |
Correct |
0 ms |
204 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
204 KB |
Output is correct |
| 2 |
Correct |
3 ms |
204 KB |
Output is correct |
| 3 |
Correct |
3 ms |
204 KB |
Output is correct |
| 4 |
Correct |
2 ms |
204 KB |
Output is correct |
| 5 |
Correct |
2 ms |
204 KB |
Output is correct |
| 6 |
Correct |
2 ms |
204 KB |
Output is correct |
| 7 |
Correct |
3 ms |
204 KB |
Output is correct |
| 8 |
Correct |
3 ms |
320 KB |
Output is correct |
| 9 |
Correct |
2 ms |
204 KB |
Output is correct |
| 10 |
Correct |
3 ms |
204 KB |
Output is correct |
| 11 |
Correct |
0 ms |
204 KB |
Output is correct |
| 12 |
Execution timed out |
1092 ms |
460 KB |
Time limit exceeded |
| 13 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
204 KB |
Output is correct |
| 2 |
Correct |
3 ms |
204 KB |
Output is correct |
| 3 |
Correct |
3 ms |
204 KB |
Output is correct |
| 4 |
Correct |
2 ms |
204 KB |
Output is correct |
| 5 |
Correct |
2 ms |
204 KB |
Output is correct |
| 6 |
Correct |
2 ms |
204 KB |
Output is correct |
| 7 |
Correct |
3 ms |
204 KB |
Output is correct |
| 8 |
Correct |
3 ms |
320 KB |
Output is correct |
| 9 |
Correct |
2 ms |
204 KB |
Output is correct |
| 10 |
Correct |
3 ms |
204 KB |
Output is correct |
| 11 |
Correct |
0 ms |
204 KB |
Output is correct |
| 12 |
Execution timed out |
1092 ms |
460 KB |
Time limit exceeded |
| 13 |
Halted |
0 ms |
0 KB |
- |
