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 |
---|---|---|---|---|---|---|---|---|---|
#352119 | #7730. Convex Checker | _Sheepsheep | WA | 51ms | 19348kb | C++17 | 7.5kb | 2024-03-12 21:16:23 | 2024-03-12 21:16:24 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std ;
#define ll long long
const int inf = 1e8 ;
const int N = 3e6+9 ;
typedef long double LD ;
const LD eps = 1e-7 ;
const LD box = 1e7 ;
int sgn( LD x )
{
return x > eps ? 1 : ( x < -eps ? -1 : 0 ) ;
}
struct point
{
LD x , y , polar_angle;
point operator + (const point &a) const
{
return{ x+a.x , y+a.y } ;
}
point operator - (const point &a) const
{
return{ x-a.x , y-a.y } ;
}
point operator * (const LD &a) const
{
return{ x*a , y*a } ;
}
point operator / (const LD &a) const
{
return{ x/a , y/a } ;
}
friend bool operator == ( const point &a , const point &b )
{
return sgn(a.x-b.x) == 0 && sgn(a.y-b.y) == 0 ;
}
friend ostream & operator << ( ostream &out , point &a )
{
out << "(" << a.x << "," << a.y << ")" ;
return out ;
}
friend istream & operator >> ( istream &in , point &a )
{
in >> a.x >> a.y ;
return in ;
}
int idx , hull_rank ;
};
struct line
{
point s , t ;
friend bool operator == ( const line &a , const line &b )
{
return (a.s==b.s&&a.t==b.t)||(a.s==b.t&&a.t==b.s) ;
}
};
LD sqr( LD x )
{
return x*x ;
}
LD mo( point x )
{
return sqrtl( sqr(x.x) + sqr(x.y) ) ;
}
LD dis( const point &a , const point &b )
{
return sqrtl( sqr(a.x-b.x) + sqr(a.y-b.y) ) ;
}
LD dot( const point &a , const point &b )
{
return a.x*b.x+a.y*b.y;
}
LD det( const point &a , const point &b )
{
// + : b ? a ??????
return a.x*b.y-b.x*a.y ;
}
bool point_on_segment( const point &a , const line &l )
{
if( l.s == l.t )
{
return a == l.s ;
}
return sgn( det(l.s-a,a-l.t) ) == 0 && sgn( dot(l.s-a,l.t-a) ) <= 0 ;
}
bool two_side( const point &a , const point &b , const line &c )
{
// ???????
return sgn( det(a-c.s,c.t-c.s) ) * sgn( det(b-c.s,c.t-c.s) ) < 0 ;
}
bool segment_inter_judge( const line &a , const line &b )
{
bool ok = 0 ;
ok |= point_on_segment( b.s , a ) ;
ok |= point_on_segment( b.t , a ) ;
ok |= point_on_segment( a.s , b ) ;
ok |= point_on_segment( a.t , b ) ;
ok |= ( two_side(a.s,a.t,b)&&two_side(b.s,b.t,a) ) ;
return ok ;
}
bool ray_inter_judge( const line &a , const line &b )
{
//??????????
return sgn( det( a.t-a.s , b.t-b.s ) ) == 0 ? 0 : 1 ;
}
LD point_to_line( const point &p , const line &l )
{
return fabs( det(l.t-l.s,p-l.s) )/dis(l.s,l.t) ;
}
LD point_to_segment( const point &p , const line &l )
{
if( l.s == l.t ) return dis( p , l.s ) ;
if( sgn( dot(l.s-p,l.t-l.s) )*sgn( dot(l.t-p,l.t-l.s) ) <= 0 ) return point_to_line(p,l) ;
else return min( dis(p,l.s) , dis(p,l.t) ) ;
}
LD arg( const line &a , const line &b )
{
LD res = dot( a.t-a.s , b.t-b.s ) ;
res /= mo( a.t-a.s ) ;
res /= mo( b.t-b.s ) ;
return acos( res ) ;
}
point line_intersect( const line &a , const line &b )
{
LD u = det( a.t-a.s,b.s-a.s ) ;
LD v = det( a.t-a.s , b.t-a.s ) ;
return ( b.s*v - b.t*u )/(v-u) ;
}
bool turn_left( const point &a , const point &b , const point &c )
{
// a ???????ac????ab??????????
return sgn( det( b-a , c-a ) ) > 0 ;
}
bool turn_right( const point &a , const point &b , const point &c )
{
return sgn( det( b-a , c-a ) ) < 0 ;
}
bool turn_left( const line &a , const line &b , const line &c )
{
// bc?????????a???
return turn_left( a.s , a.t , line_intersect(b,c) ) ;
}
int point_quadrant( const point &a )
{
if( sgn( a.x ) >= 0 && sgn( a.y ) >= 0 ) return 1 ;
else if( sgn(a.x) < 0 && sgn( a.y ) >= 0 ) return 2 ;
else if( sgn(a.x) < 0 && sgn( a.y ) < 0 ) return 3 ;
else return 4 ;
}
vector<point> convex_hull( vector<point> a )
{
vector<point>ret ;
int a_size = a.size() , ret_size = 0 ;
if( a_size <= 2 ) return a ;
sort( a.begin() , a.end() , []( point x , point y ){ return x.x == y.x ? x.y < y.y : x.x < y.x ; } ) ;
for( int i = 0 ; i < a_size ; i ++ )
{
while( ret_size > 1 && !turn_left( ret[ret_size-2] , ret[ret_size-1] , a[i] ) )
{
ret.pop_back() ; ret_size -- ;
}
ret.push_back( a[i] ) ; ret_size ++ ;
}
int fix = ret_size ;
for( int i = a_size-2 ; i >= 0 ; i -- )
{
while( ret_size > fix && !turn_left( ret[ret_size-2] , ret[ret_size-1] , a[i] ) )
{
ret.pop_back() ; ret_size -- ;
}
ret.push_back( a[i] ) ; ret_size ++ ;
}
ret.pop_back() ; ret_size -- ;
return ret ;
}
int half( const point &a ) //???????
{
return a.y > 0 || ( a.y == 0 && a.x > 0 ? 1 : 0 );
}
bool is_para( const line &a , const line &b ) //?????
{
return sgn( det(a.t-a.s,b.t-b.s) ) == 0 ;
}
bool cmp( const line &a , const line &b )
{
// (0,0) is org
int sign = half( a.t-a.s ) - half( b.t-b.s ) ; //????????
int dir = sgn( det(a.t-a.s,b.t-b.s) ) ; //????
if( sign == 0 && dir == 0 ) return sgn( det(a.t-a.s , b.t-a.s) ) < 0 ; //??????
else return sign ? sign > 0 : dir > 0 ;
//???????????
//??????????
}
vector<point> hpi( vector<line> A , LD DX , LD DY )
{
int siz_a = A.size() ;
vector<line>h ;
for( int i = 0 ; i < siz_a ; i ++ ) h.push_back( A[i] ) ;
h.push_back( {{DX,DY} , {0,DY}} ) ;
h.push_back( {{0,DY} , {0,0}} ) ;
h.push_back( {{0,0} , {DX,0}} ) ;
h.push_back( {{DX,0} , {DX,DY}} ) ;
sort( h.begin() , h.end() , cmp ) ;
vector<line> q( h.size()+10 ) ;
int l = 0 , r = -1 ;
for( auto &i : h )
{
while( l<r && !turn_left(i,q[r-1],q[r]) ) --r ;
while( l<r && !turn_left(i,q[l],q[l+1]) ) ++l ;
if( l <= r && is_para(i,q[r]) ) continue ;
q[++r] = i ;
}
while( r-l>1 && !turn_left(q[l],q[r-1],q[r]) ) --r ;
while( r-l>1 && !turn_left(q[r],q[l],q[l+1]) ) ++l ;
if( r-l < 2 ) return {} ;
vector<point> ret(r-l+1) ;
for( int i = l ; i <= r ; i ++ )
ret[i-l] = line_intersect( q[i] , q[i==r?l:i+1] ) ;
return ret ;
}
bool on_box( point a )
{
if( sgn(a.x-box) == 0 || sgn(a.y-box) == 0 ) return 1 ;
return 0;
}
bool is_open( vector<point>ret )
{
if( ret.size() <= 2 )
for( auto &u : ret ) if( on_box(u) ) return 1 ;
return 0 ;
}
void solve()
{
int n ; cin >> n ;
vector<point>a(n),b(n);
for( int i = 0 ; i < n ; i ++ )
{
cin >> a[i] ; b[i] = a[i] ;
if( i > 0 ) b[i].polar_angle = atan2( b[i].y-b[0].y , b[i].x-b[0].x ) ;
}
bool ok1 = 1 , ok2 = 1 ;
sort( b.begin()+1 , b.end() , [&]( point x , point y ){ return x.polar_angle < y.polar_angle; } ) ;
for( int i = 0 ; i < n ; i ++ ) if( !(a[i] == b[i]) ) ok1 = 0 ;
sort( b.begin()+1 , b.end() , [&]( point x , point y ){ return x.polar_angle > y.polar_angle; } ) ;
for( int i = 0 ; i < n ; i ++ ) if( !(a[i] == b[i]) ) ok2 = 0 ;
if( !ok1 && ! ok2 )
{
cout << "No\n" ; return ;
}
if( !turn_left( a[0] , a[1] , a[2] ) && !turn_right( a[0] , a[1] , a[2] ) )
{
cout << "No\n" ; return ;
}
bool ok = 1 ;
if( turn_left( a[0] , a[1] , a[2] ) )
{
for( int i = 2 ; i < n ; i ++ )
{
if( !turn_left( a[i-1] , a[i] , a[(i+1)%n] ) ) ok = 0 ;
}
}
else
{
for( int i = 2 ; i < n ; i ++ )
{
if( !turn_right( a[i-1] , a[i] , a[(i+1)%n] ) ) ok = 0 ;
}
}
if( ok ) cout << "Yes\n" ;
else cout << "No\n" ;
}
int main()
{
ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
int tt = 1 ; //cin >> tt ;
while( tt-- ) solve() ;
return 0 ;
}
/*
5 4.321
-2 -1 3 -2
1 6 3 -2
1 6 -2 -1
-3 4 3 3
-2 1 5 4
*/
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 3784kb
input:
3 0 0 1 0 0 1
output:
Yes
result:
ok answer is YES
Test #2:
score: 0
Accepted
time: 0ms
memory: 3816kb
input:
4 0 0 0 1 1 1 1 0
output:
Yes
result:
ok answer is YES
Test #3:
score: 0
Accepted
time: 0ms
memory: 3932kb
input:
4 0 0 0 3 1 2 1 1
output:
Yes
result:
ok answer is YES
Test #4:
score: 0
Accepted
time: 0ms
memory: 3788kb
input:
3 0 0 0 0 0 0
output:
No
result:
ok answer is NO
Test #5:
score: 0
Accepted
time: 0ms
memory: 3776kb
input:
5 1 0 4 1 0 1 2 0 3 2
output:
No
result:
ok answer is NO
Test #6:
score: 0
Accepted
time: 0ms
memory: 3936kb
input:
5 0 0 1000000000 0 1000000000 500000000 1000000000 1000000000 0 1000000000
output:
No
result:
ok answer is NO
Test #7:
score: 0
Accepted
time: 1ms
memory: 3772kb
input:
5 0 0 1000000000 0 1000000000 499999999 1000000000 1000000000 0 1000000000
output:
No
result:
ok answer is NO
Test #8:
score: 0
Accepted
time: 0ms
memory: 3776kb
input:
5 0 0 999999999 0 1000000000 50000000 999999999 1000000000 0 1000000000
output:
Yes
result:
ok answer is YES
Test #9:
score: 0
Accepted
time: 51ms
memory: 19348kb
input:
128312 5578014 410408218 5585076 410404717 5588011 410403262 5588473 410403033 5589740 410402405 5593295 410400643 5593751 410400417 5597248 410398684 5598935 410397848 5600618 410397014 5605185 410394751 5610514 410392111 5614281 410390245 5617263 410388768 5621142 410386847 5630840 410382045 56310...
output:
Yes
result:
ok answer is YES
Test #10:
score: -100
Wrong Answer
time: 50ms
memory: 19016kb
input:
128086 149550602 509469827 149551059 509465022 149551336 509462107 149551964 509455497 149552572 509449094 149553350 509440895 149553656 509437667 149554161 509432339 149554254 509431357 149554545 509428284 149555017 509423299 149555366 509419611 149555842 509414580 149556382 509408867 149556564 509...
output:
No
result:
wrong answer expected YES, found NO