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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
#239028#7730. Convex CheckeryuxxTL 1ms7928kbC++142.7kb2023-11-04 18:09:422023-11-04 18:09:43

Judging History

你现在查看的是最新测评结果

  • [2024-07-04 19:27:17]
  • hack成功,自动添加数据
  • (/hack/727)
  • [2024-07-04 19:17:30]
  • hack成功,自动添加数据
  • (/hack/726)
  • [2023-11-04 18:09:43]
  • 评测
  • 测评结果:TL
  • 用时:1ms
  • 内存:7928kb
  • [2023-11-04 18:09:42]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
const int N=1e5+5;
const double eps=1e-7;
int n;
struct point {
    double x, y;
    point () {}
    point (double a, double b) : x (a), y (b) {}
    bool operator<(const point &a)const{
        if(a.x==x)
        {
            return a.y>y;
        }
        return a.x>x;
    }
    point operator - (const point &b) {
        return point (x - b.x, y - b.y);
    }
};
point p[N], sp[N];
point er[N];
int cmp (double x) {
    if (fabs (x) < eps) return 0;
    return x > 0 ? 1 : -1;
}
double dis (point a, point b) {
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
double cp (point a, point b) {
    return a.x * b.y - a.y * b.x;
}
int Andrew () {
    sort(p+1,p+n+1);
    int len=0;
    for (int i=1;i<=n;i++){
        while(len>1&&cmp(cp(sp[len]-sp[len-1],p[i]-sp[len-1]))<=0) 
        {
            len--;
        }    
        sp[++len]=p[i];
    }
    int k=len;
    for(int i=n-1;i>=1;i--)
    {
        while(len>k&&cmp(cp(sp[len]-sp[len-1],p[i]-sp[len-1]))<=0)
        {   
            len--;
        }
        sp[++len]=p[i];
    }
    return len;
}

int main() 
{
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);

    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>p[i].x>>p[i].y;
        er[i]=p[i];
    }
    int t=Andrew();
    reverse(er+1,er+n+1);

    for(int i=1;i<t;i++)
    {
        sp[i+t-1]=sp[i];
    }

    
        
    if(n!=t-1)
    {
        // flag=1;
        cout<<"No";
        return 0;
    }
    // for(int i=1;i<=n;i++)
    // {
    //     cout<<er[i].x<<" "<<er[i].y<<endl;
    // }
    int flag1=0;
    int flag2=0;
    for(int i=1;i<=n+1;i++)
    {
        if(er[1].x==sp[i].x and er[1].y==sp[i].y)
        {
            for(int j=1;j<=n;j++)
            {
               //// cout<<er[j].x<<" "<<er[j].y<<" "<<sp[i+j-1].x<<" "<<sp[i+j-1].y<<endl;
                if(er[j].x!=sp[i+j-1].x or er[j].y!=sp[i+j-1].y)
                {
                    flag1=1;
                   // cout<<j<<" "<<i;
                    break;
                }
            }
            break;
        }
    }
    reverse(er+1,er+n+1);

    for(int i=1;i<=n+1;i++)
    {
        if(er[1].x==sp[i].x and er[1].y==sp[i].y)
        {
            for(int j=1;j<=n;j++)
            {
                if(er[j].x!=sp[i+j-1].x or er[j].y!=sp[i+j-1].y)
                {
                    flag2=1;
                    //cout<<j<<" "<<i;
                    break;
                }
            }
            break;
        }
    }
    if(flag1 and flag2)
    {
        cout<<"No";
    }
    else
    {
        cout<<"Yes";
    }
    

    return 0;
}

详细

Test #1:

score: 100
Accepted
time: 1ms
memory: 5928kb

input:

3
0 0
1 0
0 1

output:

Yes

result:

ok answer is YES

Test #2:

score: 0
Accepted
time: 1ms
memory: 7928kb

input:

4
0 0
0 1
1 1
1 0

output:

Yes

result:

ok answer is YES

Test #3:

score: 0
Accepted
time: 1ms
memory: 5916kb

input:

4
0 0
0 3
1 2
1 1

output:

Yes

result:

ok answer is YES

Test #4:

score: 0
Accepted
time: 1ms
memory: 7832kb

input:

3
0 0
0 0
0 0

output:

No

result:

ok answer is NO

Test #5:

score: 0
Accepted
time: 1ms
memory: 5928kb

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: 1ms
memory: 5796kb

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: 7904kb

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: 1ms
memory: 7848kb

input:

5
0 0
999999999 0
1000000000 50000000
999999999 1000000000
0 1000000000

output:

Yes

result:

ok answer is YES

Test #9:

score: -100
Time Limit Exceeded

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:


result: