제출 #899361

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
899361		votranngocvy	Zvijezda (COCI19_zvijezda)	C++14	110 / 110	104 ms	8056 KiB

zvijezda

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define ld long double
#define pii pair<int,int>
#define fi first
#define se second
#define mp make_pair
const int N = 1e5 + 5;
pii a[N];
int n,x,y;

ld ccw(pii a,pii b,pii c) {
    return (ld)a.fi * (b.se - c.se) + (ld)b.fi * (c.se - a.se) + (ld)c.fi * (a.se - b.se);
}

bool calc(int i) {
    return ccw(a[i],a[(i + 1) % n],mp(x,y)) >= 0;
}

int tknp(int l,int r) {
    int low = l,high = r;
    while (low < high) {
        int mid = (low + high + 1) / 2;
        if (calc(l) == calc(mid)) low = mid;
        else high = mid - 1;
    }
    int ans = low - l + 1;
    if (!calc(l)) return n / 2 - ans;
    return ans;
}

bool solve() {
    int a = calc(0),b = calc(n / 2);
    if (a == b) return a;
    return (tknp(0,n / 2 - 1) + tknp(n / 2,n - 1)) >= (n / 2 + 1);
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t;
    cin >> t >> n;
    for (int i = 0; i < n; i++) cin >> a[i].fi >> a[i].se;
    int q;
    cin >> q;
    int cnt = 0;
    while (q--) {
        cin >> x >> y;
        x ^= t * cnt * cnt * cnt;
        y ^= t * cnt * cnt * cnt;
        int ans = solve();
        cnt += ans;
        if (ans) cout << "DA\n";
        else cout << "NE\n";
    }
}

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60