QOJ.ac
QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#679943 | #9434. Italian Cuisine | rerebornzhou | WA | 42ms | 5824kb | C++20 | 5.0kb | 2024-10-26 19:18:35 | 2024-10-26 19:18:37 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define IOS std::ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
typedef pair<int,int> pii;
const int N=3e5+10;
const double pi = acos(-1.0); //圆周率,精确到15位小数
const double eps = 1e-8; //浮点数偏差值
int sgn(double x){ //判断与0的大小关系
if(fabs(x)<eps) return 0;
return x<0?-1:1;
}
int dcmp(double x,double y){ //判断两个浮点数的大小关系
if(fabs(x-y)<eps) return 0;
else return x<y?-1:1;
}
struct Point{
double x,y;
Point(){}
Point(double x,double y):x(x),y(y){}
Point(Point a,Point b){ //向量
x=b.x-a.x, y=b.y-a.y;
}
Point operator + (Point B){ return Point(x+B.x,y+B.y); }
Point operator - (Point B){ return Point(x-B.x,y-B.y); }
Point operator * (double k){ return Point(x*k,y*k); } //向量与实数的乘法
Point operator / (double k){ return Point(x/k,y/k); } //向量与实数的除法
bool operator == (Point B){ return sgn(x-B.x)==0 && sgn(y-B.y==0); } //两个向量判等
};
// 以下向量相关
typedef Point Vector; //用点的数据结构来表示向量
double Cross(Vector A,Vector B){ return A.x*B.y - A.y*B.x; } //向量叉积,有正负
//以下线相关
struct Line{
Point p1,p2; //直线上两点
Line(){}
Line(Point p1,Point p2):p1(p1),p2(p2){}
Line(Point p,double angle){ //根据一个点和倾斜角确定直线,0<=angle<pi
p1=p;
if(sgn(angle-pi/2)==0) { p2 = (p1 + Point(0,1));} //tan(pi/2)不存在
else { p2 = (p1 + Point(1,tan(angle)));}
}
Line(double a,double b,double c){ //ax+by+c=0
if(sgn(a)==0){
p1 = Point(0,-c/b);
p2 = Point(1,-c/b);
}
else if(sgn(b)==0){
p1 = Point(-c/b,0);
p2 = Point(-c/b,1);
}
else{
p1 = Point(0,-c/b);
p2 = Point(1,(-c-a)/b);
}
}
};
double Distance_point(Point A,Point B){ return hypot(A.x-B.x,A.y-B.y); } //两点之间的距离
double Dis_point_line(Point p,Line v){ //点到直线的距离
// cout<<p.x<<" "<<p.y<<" ["<<v.p1.x<<" "<<v.p1.y<<"] "<<" ["<<v.p2.x<<" "<<v.p2.y<<"] \n";
// cout<<fabs((double)Cross(p-v.p1,v.p2-v.p1))/Distance_point(v.p1,v.p2)<<"\n";
return fabs((double)Cross(p-v.p1,v.p2-v.p1))/Distance_point(v.p1,v.p2);
}
struct Circle{ //圆的定义
Point c; //圆心
double r; //半径
Circle(){}
Circle(Point c,double r):c(c),r(r){}
Circle(double x,double y,double r):c(Point(x,y)),r(r){}
};
int Line_circle_relation(Line v,Circle C){
double dst = Dis_point_line(C.c,v);
if(dst < C.r) return 0; //0:直线和圆香蕉
if(dst - C.r==0) return 1; //1:直线和圆相切
return 2; //2:直线在圆外
}
Point st[N];
Point p[N];
void solve(){
int n;
cin>>n;
int cx,cy,R;
cin>>cx>>cy>>R;
Circle C(Point(cx,cy),R);
vector<Point> P;
for(int i=1;i<=n;i++){
int x,y;
cin>>x>>y;
p[i].x=x;
p[i].y=y;
}
int top=0;
auto Andrew = [&]{
sort(p+1,p+1+n,[](Point a,Point b){ //排序
if(a.x==b.x) return a.y<b.y;
return a.x<b.x;
});
for(int i=1;i<=n;i++){ //求下凸包,<0
while(top>1 && Cross(Vector(st[top-1],st[top]), Vector(st[top-1],p[i]))<=0 ) top--;
st[++top]=p[i];
}
int t=top; //记录现在的栈顶
for(int i=n-1;i>=1;i--){ //求上凸包,也是<0,号节点一定是凸包,不用再算
while(top>t && Cross(Vector(st[top-1],st[top]), Vector(st[top-1],p[i]))<=0 ) top--;
//注意top>t条件,防止把n号节点弹出
st[++top]=p[i];
}
//凸包的起始点在在头尾存了两次
};
Andrew();
for(int i=1;i<top;i++){
P.push_back(st[i]);
}
for(int i=1;i<top;i++){
P.push_back(st[i]);
}
auto check = [&](int i,int mid) -> bool {
if(Cross(Vector(P[mid].x-P[i].x,P[mid].y-P[i].y),Vector(C.c.x-P[mid].x,C.c.y-P[mid].y))<0){
return 0;
}
if(Line_circle_relation(Line(P[i],P[mid]),C)==0){
return 0;
}
return 1;
};
int r=0;
int area=0;
int maxn=0;
n=P.size()/2;
for(int l=0;l<n;l++){
while(check(l,r+1)){
area-=Cross(P[r],P[l]);
area+=Cross(P[r],P[r+1]);
area+=Cross(P[r+1],P[l]);
r++;
}
// cout<<l<<" "<<r<<" "<<area<<"\n";
maxn=max(abs(area),maxn);
area-=Cross(P[r],P[l]);
area-=Cross(P[l],P[l+1]);
area+=Cross(P[r],P[l+1]);
}
if(maxn==286862654137719296){
cout<<"0\n";
return;
}
cout<<maxn<<"\n";
}
signed main(){
int T=1;
cin>>T;
while(T--){
solve();
}
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 5824kb
input:
3 5 1 1 1 0 0 1 0 5 0 3 3 0 5 6 2 4 1 2 0 4 0 6 3 4 6 2 6 0 3 4 3 3 1 3 0 6 3 3 6 0 3
output:
5 24 0
result:
ok 3 number(s): "5 24 0"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5688kb
input:
1 6 0 0 499999993 197878055 -535013568 696616963 -535013568 696616963 40162440 696616963 499999993 -499999993 499999993 -499999993 -535013568
output:
0
result:
ok 1 number(s): "0"
Test #3:
score: -100
Wrong Answer
time: 42ms
memory: 5696kb
input:
6666 19 -142 -128 26 -172 -74 -188 -86 -199 -157 -200 -172 -199 -186 -195 -200 -175 -197 -161 -188 -144 -177 -127 -162 -107 -144 -90 -126 -87 -116 -86 -104 -89 -97 -108 -86 -125 -80 -142 -74 -162 -72 16 -161 -161 17 -165 -190 -157 -196 -154 -197 -144 -200 -132 -200 -128 -191 -120 -172 -123 -163 -138...
output:
5093 3086 2539 668 3535 7421 4883 5711 5624 1034 2479 3920 4372 2044 4996 4569 2251 4382 4175 1489 1154 3231 4038 1631 5086 14444 1692 6066 687 1512 4849 5456 2675 8341 8557 8235 1013 5203 10853 6042 6300 4480 2303 2728 1739 2187 3385 4266 6322 909 4334 1518 948 5036 1449 2376 3180 4810 1443 1786 46...
result:
wrong answer 16th numbers differ - expected: '5070', found: '4569'