| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 887743 |
2023-12-15T07:08:54 Z |
ad_red |
Tri (CEOI09_tri) |
C++17 |
|
623 ms |
5200 KB |
#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int 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) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> B;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}());
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head
const int N=100100;
const int S=sqrt(N*15);
int n,m;
struct pt {
int x,y;
pt(int _x=0,int _y=0) : x(_x),y(_y) {}
}p[N];
vector<pt> ch[N];
int 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);
}
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;
}
int 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+1) {
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&&orient(hull[SZ(hull)-2],hull[SZ(hull)-1],p)>=0) {
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);
int L,R;
{
L=n-1;
int low=0,high=n-1;
while (low<=high) {
int mid=low+high>>1;
if (orient(p[mid],pt(0,0),a)>=0) {
L=mid;
high=mid-1;
} else {
low=mid+1;
}
}
}
{
R=0;
int low=0,high=n-1;
while (low<=high) {
int 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--;
}
assert(L%S==0);
assert((R + 1)%S==0);
rep(i,L/S,R/S+1) {
int sz=SZ(ch[i]);
int low=0,high=sz-1;
while (low<=high) {
int 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
tri.cpp: In function 'int main()':
tri.cpp:76:20: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
76 | int mid=low+high>>1;
| ~~~^~~~~
tri.cpp:89:20: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
89 | int mid=low+high>>1;
| ~~~^~~~~
tri.cpp:125:20: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
125 | int mid=low+high>>1;
| ~~~^~~~~
tri.cpp:47:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
47 | scanf("%d%d",&n,&m);
| ~~~~~^~~~~~~~~~~~~~
tri.cpp:49:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
49 | scanf("%d%d",&p[i].x,&p[i].y);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
tri.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
69 | scanf("%d%d%d%d",&a.x,&a.y,&b.x,&b.y);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
3420 KB |
Output is correct |
| 2 |
Correct |
4 ms |
3416 KB |
Output is correct |
| 3 |
Correct |
85 ms |
3912 KB |
Output is correct |
| 4 |
Correct |
271 ms |
4440 KB |
Output is correct |
| 5 |
Correct |
623 ms |
4944 KB |
Output is correct |
| 6 |
Correct |
400 ms |
4548 KB |
Output is correct |
| 7 |
Correct |
554 ms |
5200 KB |
Output is correct |
| 8 |
Correct |
211 ms |
4444 KB |
Output is correct |
| 9 |
Correct |
244 ms |
4592 KB |
Output is correct |
| 10 |
Correct |
277 ms |
5052 KB |
Output is correct |
