# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
121205 | _7_7_ | Triangles (CEOI18_tri) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#include "trilib.h"
using namespace std;
const int N = 1e5 + 11;
int n;
long long *x, *y;
int queries=0;
bool was[N];
static void init() {
static int is_inited=0;
if (is_inited)
return;
is_inited=1;
assert(scanf("%d", &n)==1);
x=(long long*)malloc((n+1)*sizeof(long long));
y=(long long*)malloc((n+1)*sizeof(long long));
for (int i=1; i<=n; i++)
assert(scanf("%lld%lld", &x[i], &y[i])==2);
}
int get_n() {
init();
return n;
}
int is_clockwise(int a, int b, int c) {
init();
assert(a>=1 && a<=n);
assert(b>=1 && b<=n);
assert(c>=1 && c<=n);
assert(a!=b && a!=c && b!=c);
queries++;
if(queries == 1000 * 1000 + 1)
printf("Too many queries!");
return (x[b]-x[a])*(y[c]-y[a])-(x[c]-x[a])*(y[b]-y[a])<0;
}
void give_answer(int s) {
init();
s = 0;
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= n; ++j) {
if (i == j)
continue;
bool ok = 1;
for (int x = 1; x <= n; ++x) {
if (i == x || j == x)
continue;
if (!is_clockwise(i, j, x)) {
ok = 0;
break;
}
}
if (ok) {
if (!was[i]) {
++s;
was[i] = 1;
}
if (!was[j]) {
was[j] = 1;
++s;
}
}
}
printf("%d\n", s);
}