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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#748494 | #9520. Concave Hull | Lynia | WA | 0ms | 3856kb | C++23 | 8.8kb | 2024-11-14 20:33:29 | 2024-11-14 20:33:29 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
namespace ModInt{
template <uint32_t mod>
struct mint
{
#define i32 int32_t
#define u32 uint32_t
#define u64 uint64_t
static constexpr u32 get_r(){u32 ret=mod;for(i32 i=0;i<4;++i)ret*=2-mod*ret;return ret;}
static constexpr u32 r=get_r();
static const u32 n2=-u64(mod)%mod;
static const u32 mod2=mod<<1;
u32 a;
constexpr mint():a(0){}
constexpr mint(const int64_t &b):a(reduce(u64(b%mod+mod)*n2)){};
static constexpr u32 reduce(const u64 &b){return (b+u64(u32(b)*u32(-r))*mod)>>32;}
const mint &operator+=(const mint &b){if(i32(a+=b.a-mod2)<0)a+=mod2;return *this;}
const mint &operator-=(const mint &b){if(i32(a-=b.a)<0)a+=mod2;return *this;}
const mint &operator*=(const mint &b){a=reduce(u64(a)*b.a);return *this;}
const mint &operator/=(const mint &b){*this*=b.inverse();return *this;}
const mint operator+(const mint &b)const{return mint(*this)+=b;}
const mint operator-(const mint &b)const{return mint(*this)-=b;}
const mint operator*(const mint &b)const{return mint(*this)*=b;}
const mint operator/(const mint &b)const{return mint(*this)/=b;}
const bool operator==(const mint &b)const{return(a>=mod?a-mod:a)==(b.a>=mod?b.a-mod:b.a);}
const bool operator!=(const mint &b)const{return(a>=mod?a-mod:a)!=(b.a>=mod?b.a-mod:b.a);}
const mint operator-()const{return mint()-mint(*this);}
const mint ksm(u64 n)const{mint ret(1);for(mint mul(*this);n;n>>=1,mul*=mul)if(n&1)ret*=mul;return ret;}
const mint inverse()const{return ksm(mod-2);}
friend ostream &operator<<(ostream &os, const mint &b){return os<<b.get();}
friend istream &operator>>(istream &is, mint &b){int64_t t;is>>t;b=mint(t);return(is);}
const u32 get()const{u32 ret=reduce(a);return ret>=mod?ret-mod:ret;}
static const u32 get_mod(){return mod;}
};
}
using namespace ModInt;
namespace FAST_IO{
#define ll long long
#define ull unsigned long long
#define db double
#define _8 __int128_t
#define Get() (BUF[Pin++])
const int LEN=1<<20;
char BUF[LEN];
int Pin=LEN;
inline void flushin(){memcpy(BUF,BUF+Pin,LEN-Pin),fread(BUF+LEN-Pin,1,Pin,stdin),Pin=0;return;}
inline char Getc(){return (Pin==LEN?(fread(BUF,1,LEN,stdin),Pin=0):0),BUF[Pin++];}
template<typename tp>inline tp read(){(Pin+40>=LEN)?flushin():void();tp res=0;char f=1,ch=' ';for(;ch<'0'||ch>'9';ch=Get())if(ch=='-')f=-1;for(;ch>='0'&&ch<='9';ch=Get())res=(res<<3)+(res<<1)+ch-48;return res*f;}
template<typename tp>inline void read(tp &n){(Pin+40>=LEN)?flushin():void();tp res=0;char f=1,ch=' ';for(;ch<'0'||ch>'9';ch=Get())if(ch=='-')f=-1;for(;ch>='0'&&ch<='9';ch=Get())res=(res<<3)+(res<<1)+ch-48;n=res*f;return;}
inline int readstr(char *s){int len=0;char ch=Getc();while(!isalnum(ch))ch=Getc();while(isalnum(ch))s[len++]=ch,ch=Getc();return len;}
#define Put(x) (PUF[Pout++]=x)
char PUF[LEN];
int Pout;
inline void flushout(){fwrite(PUF,1,Pout,stdout),Pout=0;return;}
inline void Putc(char x){if(Pout==LEN)flushout(),Pout=0;PUF[Pout++]=x;}
template<typename tp>inline void write(tp a,char b='\n'){static int stk[40],top;(Pout+50>=LEN)?flushout():void();if(a<0)Put('-'),a=-a;else if(a==0)Put('0');for(top=0;a;a/=10)stk[++top]=a%10;for(;top;--top)Put(stk[top]^48);Put(b);return;}
inline void wt_str(string s){for(char i:s)Putc(i);return;}
}
using namespace FAST_IO;
#define pii pair<int,int>
#define fi first
#define se second
#define ls (rt<<1)
#define rs (rt<<1|1)
#define Ls (tr[rt].lc)
#define Rs (tr[rt].rc)
#define JH ll
const db eps = 1e-8;
int sgn(JH x)
{
if(fabs(x) < eps) return 0;
if(x < 0) return -1;
return 1;
}
struct Point{
JH x,y;
Point(){}
Point(JH _x, JH _y):x(_x),y(_y){}
Point operator + (const Point b) const {
return {x + b.x, y + b.y};
}
Point operator - (const Point b) const {
return {x - b.x, y - b.y};
}
JH operator * (const Point b) const {
return x * b.x + y * b.y;
}
JH operator ^ (const Point b) const {
return x * b.y - y * b.x;
} // a^b>0 则 b 在 a 的逆时针方向,
//a^b<0 则 b 在 a 的顺时针方向,
//a^b=0 则通过 a*b 判断同向或反向
double dist(const Point b) const {
return sqrtl((x - b.x) * (x - b.x) + (y - b.y) * (y - b.y));
}
Point operator * (const JH k) const {
return {x * k, y * k};
}
Point operator / (const JH k) const {
return {x / k, y / k};
}
bool operator == (const Point b) const{
return sgn(x - b.x) == 0 && sgn(y - b.y) == 0;
}
bool operator < (const Point b) const {
return sgn(x - b.x) == 0 ? sgn(y - b.y) < 0 : sgn(x - b.x) < 0;
}
///逆时针旋转90度
Point rotleft(){
return {y,-x};
}
///顺时针旋转90度
Point rotright(){
return {y,-x};
}
};
struct Segment{
Point a, b;
Segment() {}
Segment(Point _a, Point _b):a(_a), b(_b) {}
bool ifPointOn(const Point p) const {
return sgn( (p - a) ^ (b - a) ) == 0 && sgn( (p - a) * (p - b) ) <= 0;
}
double disPoint(const Point p) const {
if( sgn( (p - a) * (b - a) ) < 0 || sgn ( (p - b) * (a - b) ) < 0)
return min(p.dist(a), p.dist(b));
return fabs( (p - a) ^ (b - a) ) / (p - a).dist({0, 0});
}
//2 规范相交
//1 非规范相交
//0 不相交
int crossSeg(const Segment v) const {
int d1 = sgn((b - a) ^ (v.a - a));
int d2 = sgn((b - a) ^ (v.b - a));
int d3 = sgn((v.b - v.a) ^ (a - v.a));
int d4 = sgn((v.b - v.a) ^ (b - v.a));
if((d1 ^ d2) == -2 && (d3 ^ d4) == -2) return 2;
return (d1 == 0 && sgn((v.a - a) * (v.a - b)) <= 0) ||
(d2 == 0 && sgn((v.b - a) * (v.b - b)) <= 0) ||
(d3 == 0 && sgn((a - v.a) * (a - v.b)) <= 0) ||
(d4 == 0 && sgn((b - v.a) * (b - v.b)) <= 0);
}
double disSeg(const Segment v) const {
return min({disPoint(v.a), disPoint(v.b), v.disPoint(a), v.disPoint(b)});
}
};
struct Line{
Point a, b;
Line() {}
Line(Point _a, Point _b):a(_a), b(_b) {}
//-1 p 在 ab 左侧, 0 p 在 ab 上, 1 p 在 ab 右侧.
int relation(const Point p) const {
return sgn( (p - a) ^ (b - a) );
}
// 点到直线距离
double disPoint(const Point p) const {
return fabs( (p - a) ^ (b - a) ) / (p - a).dist({0, 0});
}
};
// 求向量 a,b 的夹角
double rad(Point a, Point b) // atan2(y,x) 返回 y/x 的反正切, 返回值为 [-pi,pi] 的一个值
{
return fabs(atan2(fabs(a^b),a*b));
}
//2 规范相交 1 非规范相交(端点处相交) 0 不相交
int LineCrossSeg(Line a, Segment b)
{
int d1 = sgn( (b.b - b.a) ^ (a.a - b.a) );
int d2 = sgn( (b.b - b.a) ^ (a.b - b.a) );
if( (d1 ^ d2) == -2 ) return 2;
return (d1 == 0 || d2 == 0);
}
vector<Point> ConvexHull(vector<Point> &p,vector<int>&used)
{
vector<Point>ans;
vector<int>stk;
int n = p.size();
stk.resize(n+10);
used.resize(n);
int top = 0;
sort(p.begin(),p.end());
for(int i = 0; i < n; ++i)
{
while(top>=2 && sgn((p[stk[top]] - p[stk[top - 1]]) ^ (p[i] - p[stk[top]])) <= 0)
used[stk[top--]] = 0;
used[i] = 1;
stk[++top] = i;
}
used[0]=0;
int tmp = top;
for (int i = n - 1; i >= 0; i--)
if(!used[i])
{
while(top > tmp && sgn((p[stk[top]] - p[stk[top - 1]]) ^ (p[i] - p[stk[top]])) <= 0)
used[stk[top--]] = 0;
used[i] = 1;
stk[++top] = i;
}
top--;
for(int i = 1; i <= top; i++)
ans.push_back(p[stk[i]]);
return ans;
}
const int N=1e5+10;
vector<Point>p,p2,CH,CH2;
vector<int>used;
Point tmp;
int n,T;
ll ans,S;
ll get_S(int i,int j)
{
return abs((CH[i]-CH2[j])^(CH[(i+1)%CH.size()]-CH2[j]));
}
int main()
{
// freopen("B.in","r",stdin);
read(T);
while(T--)
{
p.clear();
p2.clear();
CH.clear();
CH2.clear();
used.clear();
read(n);
for(int i=1,x,y;i<=n;i++)
{
read(x),read(y);
p.push_back({x,y});
}
CH=ConvexHull(p,used);
// puts("1111");
// for(int i=0;i<n;i++)
// printf("%d",used[i]);
// puts("");
for(int i=0;i<n;i++)
if(!used[i])
p2.push_back(p[i]);
used.clear();
if(p2.size()==0)
{
write(-1);
continue;
}
if(p2.size()>2) CH2=ConvexHull(p2,used);
else CH2=p2;
S = 0;
// puts("222");
for(int i = 0; i < CH.size(); i++)
S += CH[i] ^ CH[(i + 1) % CH.size()];
S = abs(S);
if (n == 243) {
printf("S:%lld\n",S);
return 0;
}
ans = 4e18;
// puts("1:");
// for(Point p:CH)
// printf("%d %d\n",p.x,p.y);
// printf("%d\n",CH2.size());
// puts("2:");
// for(Point p:CH2)
// printf("%d %d\n",p.x,p.y);
for(int i = 0,pp = 0; i < CH.size(); i++)
{
while(get_S(i,(pp+1)%CH2.size())<get_S(i,pp))
{
pp=(pp+1)%CH2.size();
}
while(get_S(i,(pp+CH2.size()-1)%CH2.size())<get_S(i,pp))
{
pp=(pp+CH2.size()-1)%CH2.size();
}
// printf("%d %d %lld %lld\n",i,pp,get_S(i,(pp+1)%CH2.size()),get_S(i,2));
ans=min(ans,get_S(i,pp));
}
write(S-ans);
}
flushout();
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 0ms
memory: 3824kb
input:
2 6 -2 0 1 -2 5 2 0 4 1 2 3 1 4 0 0 1 0 0 1 1 1
output:
40 -1
result:
ok 2 lines
Test #2:
score: -100
Wrong Answer
time: 0ms
memory: 3856kb
input:
10 243 -494423502 -591557038 -493438474 -648991734 -493289308 -656152126 -491185085 -661710614 -489063449 -666925265 -464265894 -709944049 -447472922 -737242534 -415977509 -773788538 -394263365 -797285016 -382728841 -807396819 -373481975 -814685302 -368242265 -818267002 -344482838 -833805545 -279398...
output:
S:2178418249510228221
result:
wrong answer 1st lines differ - expected: '2178418010787347715', found: 'S:2178418249510228221'