| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 991431 | Andrey | Portal (BOI24_portal) | 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>
using namespace std;
long long gcd(long long a, long long b) {
if(b < 0) {
b = abs(b);
}
if(a < 0) {
a = abs(a);
}
if(b == 0) {
return a;
}
return gcd(b,a%b);
}
long long lcm(long long a, long long b) {
a = abs(a);
b = abs(b);
return (a/gcd(a,b))*b;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
long long n,a,b,ans = 0,x = 0;
cin >> n;
vector<pair<long long,long long>> haha(n);
for(long long i = 0; i < n; i++) {
cin >> a >> b;
haha[i] = {a,b};
}
vector<pair<long long,long long>> yay(0);
for(long long i = 1; i < n; i++) {
yay.push_back({haha[i].first-haha[i-1].first,haha[i].second-haha[i-1].second});
}
for(long long i = 0; i < yay.size(); i++) {
x = gcd(x,yay[i].second);
for(long long j = i+1; j < min(i+2,yay.size()); j++) {
if(yay[i].second == 0) {
ans = gcd(ans,yay[i].first);
}
else if(yay[j].second == 0) {
ans = gcd(ans,yay[j].first);
}
else {
long long a = yay[i].first,b = -yay[i].second,c = yay[j].first,d = -yay[j].second;
ans = gcd(ans,a*(lcm(b,d)/b)-c*(lcm(b,d)/d));
}
}
}
if(ans*x == 0) {
cout << -1;
}
else {
cout << abs(ans*x);
}
return 0;
}