| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 888605 | ad_red | Tri (CEOI09_tri) | C++17 | 505 ms | 6484 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;
typedef long long ll;
#define rep(i,a,n) for (ll i=a;i<n;i++)
#define per(i,a,n) for (ll i=n-1;i>=a;i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((ll)(x).size())
typedef vector<ll> VI;
typedef basic_string<int> B;
typedef pair<ll,ll> PII;
// head
const ll N=100100;
const ll S=1200;
ll n,m;
struct pt {
ll x,y;
pt(ll _x=0,ll _y=0) : x(_x),y(_y) {}
}p[N];
ll vp(pt a, pt b) {
return a.x * b.y - b.x * a.y;
}
vector<pt> ch[N];
ll orient(pt a,pt b,pt c) {
ll v=(b.y-a.y)*1ll*(c.x-b.x)-(b.x-a.x)*1ll*(c.y-b.y);
return v==0?0:(v<0?-1:1);
}
ll sgn(pt a, pt b, pt c) {
// -1 if the order is A-B-C from left to right if B is the bottom point
// 1 or 0 otherwise
ll q = (a.x - b.x) * (c.y - b.y) - (a.y - b.y) * (c.x - b.x);
return q == 0 ? 0 : (q < 0 ? -1 : 1);
}
bool const operator<(const pt& a,const pt& b) {
if (orient(pt(0,0),a,b)==0) {
return (a.x==b.x?a.y<b.y:a.x<b.x);
}
return orient(pt(0,0),a,b)>0;
}
bool in_tri(pt a,pt b,pt c,pt p) {
return orient(a,b,p)!=-1&&orient(b,c,p)!=-1&&orient(c,a,p)!=-1;
}
signed main() {
scanf("%d%d",&n,&m);
rep(i,0,n) {
scanf("%d%d",&p[i].x,&p[i].y);
}
sort(p,p+n);
rep(i,0,n) {
ch[i/S].pb(p[i]);
}
rep(i,0,n) {
if (ch[i].empty()) continue;
vector<pt> hull;
sort(all(ch[i]),[&](pt a,pt b) { return a.x<b.x||(a.x==b.x&&a.y<b.y); });
for (auto& p:ch[i]) {
while (SZ(hull)>=2 && sgn(hull[SZ(hull)-2], p, hull[SZ(hull)-1]) <= 0LL) {
hull.pop_back();
}
hull.pb(p);
}
ch[i]=hull;
}
while (m--) {
pt a,b;
scanf("%d%d%d%d",&a.x,&a.y,&b.x,&b.y);
if (orient(b,pt(0,0),a)<=0) swap(a,b);
ll L,R;
{
L=n-1;
ll low=0,high=n-1;
while (low<=high) {
ll mid=low+high>>1;
if (orient(p[mid],pt(0,0),a)>=0) {
L=mid;
high=mid-1;
} else {
low=mid+1;
}
}
}
{
R=0;
ll low=0,high=n-1;
while (low<=high) {
ll mid=low+high>>1;
if (orient(p[mid],pt(0,0),b)<=0) {
R=mid;
low=mid+1;
} else {
high=mid-1;
}
}
}
if (L>R) {
printf("N\n");
continue;
}
if (R-L<=S) {
bool ok=false;
rep(i,L,R+1) if (in_tri(a,b,pt(0,0),p[i])) ok=true;
puts(ok?"Y":"N");
continue;
}
bool ok=false;
while (L%S!=0) {
if (in_tri(a,b,pt(0,0),p[L])) ok=true;
L++;
}
while (R>=L&&R%S!=S-1) {
if (in_tri(a,b,pt(0,0),p[R])) ok=true;
R--;
}
rep(i,L/S,R/S+1) {
ll sz=SZ(ch[i]);
ll low=0,high=sz-1;
while (low<=high) {
ll mid=low+high>>1;
if (in_tri(a,b,pt(0,0),ch[i][mid])) {
ok=true;
break;
}
if (mid+1==sz||(!in_tri(a,b,pt(0,0),ch[i][mid+1])&&orient(ch[i][mid],a,ch[i][mid+1])==1)) {
high=mid-1;
} else {
low=mid+1;
}
}
if (ok) break;
}
puts(ok?"Y":"N");
}
}
Compilation message (stderr)
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