| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1294924 | TIN | Hexagonal Territory (APIO21_hexagon) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
using namespace std;
#define FNAME "test"
const int MOD = 1e9 + 7;
void Task() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(FNAME".inp","r")) {
freopen(FNAME".inp","r",stdin);
freopen(FNAME".out","w",stdout);
}
}
const int dx[] = {+1,+1, 0,-1,-1, 0};
const int dy[] = { 0,-1,-1, 0,+1,+1};
long long computeArea(const vector<pair<long long, long long>>& points) {
long long ret = 0;
int n = (int) points.size();
for (int i = 0; i < n; ++i) ret += points[i].first * points[(i + 1) % n].second;
for (int i = 0; i < n; ++i) ret -= points[i].second * points[(i + 1) % n].first;
ret /= 2;
return abs(ret);
}
void Solve() {
int N; cin >> N;
vector<pair<long long, long long>> points; points.push_back({0, 0});
long long B = 0;
for (int i = 1; i <= N; ++i) {
int dir; cin >> dir; --dir;
long long step; cin >> step;
long long nx = points.back().first + step * dx[dir];
long long ny = points.back().second + step * dy[dir];
B += step;
points.push_back({nx, ny});
}
long long S = computeArea(points);
// I = S - B / 2 + 1
long long ans = S - B / 2 + 1; ans %= MOD;
ans = (ans + B) % MOD;
cout << ans;
}
int main(void) {
Task();
Solve();
return 2801^2801;
}