QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#578030#8082. Minimum Euclidean DistanceAuroraaAC ✓10ms4040kbC++206.8kb2024-09-20 16:07:182024-09-20 16:07:18

Judging History

你现在查看的是最新测评结果

  • [2024-09-20 16:07:18]
  • 评测
  • 测评结果:AC
  • 用时:10ms
  • 内存:4040kb
  • [2024-09-20 16:07:18]
  • 提交

answer

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
#define int long long
#define double long double
const int N=1e5+5;
const double pi=acos(-1);
const double eps=1e-8;
int sgn(double x){
    if(fabs(x)<=eps)return 0;
    return x<0?-1:1;
}
struct Point{
    double x,y;
    Point(){}
    Point(double x,double y):x(x),y(y){}
    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};}
    double cross(const Point&a)const{return x*a.y-y*a.x;}
    int toleft(const Point&a)const{return sgn(cross(a));}
    double dot(const Point&a)const{return x*a.x+y*a.y;}
    bool operator<(const Point&a)const{
        if(x==a.x)return y<a.y;
        return x<a.x;
    }
    bool operator==(const Point&a)const{return x==a.x && y==a.y;}
    double dis2(const Point&a)const{return (x-a.x)*(x-a.x)+(y-a.y)*(y-a.y);}
    double dis(const Point&a)const{return sqrt(dis2(a));}
    double len()const{return sqrt(x*x+y*y);}
};
struct Segment{
    Point a,b;
    Segment(){}
    Segment(Point a,Point b):a(a),b(b){}
    bool operator<(const Segment&s)const{
        return make_pair(a,b)< make_pair(s.a,s.b);
    }
    int is_on(const Point&p)const{
        if(p==a || p==b)return -1;
        return (p-a).toleft(p-b)==0 && (p-a).dot(p-b)<0;
    }
    double dis(const Point&p)const{
        if(sgn((p-a).dot(b-a))==-1 || sgn((p-b).dot(a-b))==-1)return min(p.dis(a),p.dis(b));
        Point p0=a,v=b-a;
        return abs(v.cross(p-p0)/v.len());
    }
};
struct Convex{
    vector<Point>p;
    // -1 在边上 | 0 在外部 | 1 在内部
    int is_in(const Point&a)const{
        if(p.size()==1)return a==p[0]?-1:0;
        if(p.size()==2)
        if(a==p[0])return -1;
        if((p[1]-p[0]).toleft(a-p[0])==-1 || (p.back()-p[0]).toleft(a-p[0])==1)return 0;
        auto cmp=[&](const Point&u,const Point&v){
            return (u-p[0]).toleft(v-p[0])==1;
        };
        int pos=lower_bound(p.begin()+1,p.end(),a,cmp)-p.begin();
        if(pos==1)return Segment(p[0],p[1]).is_on(a)?-1:0;
        if(pos==p.size()-1 && Segment(p[0],p[pos]).is_on(a))return -1;
        if(Segment(p[pos-1],p[pos]).is_on(a))return -1;
        return (p[pos]-p[pos-1]).toleft(a-p[pos-1])>0;
    }
    // 返回切点下标
    int find_max(const Point u){
        int l=0,r=p.size()-1;
        // x 的极角序小于 y
        auto cmp=[&](const Point&x,const Point&y){
            return (x-u).toleft(y-u)==1;
        };
        if(cmp(p[0],p.back())){     // 极值在 p[back]
            while(l<r){
                int mid=(l+r)>>1;
                if(cmp(p[r],p[mid]) && cmp(p[mid+1],p[mid]))r=mid;
                else l=mid+1;
            }
        }
        else{       // 极值在 p[0]
            while(l<r){
                int mid=(l+r+1)>>1;
                if(cmp(p[l],p[mid]) && cmp(p[mid-1],p[mid]))l=mid;
                else r=mid-1;
            }
        }
        return l;
    }
    int find_min(const Point u){
        int l=0,r=p.size()-1;
        // x 的极角序大于 y
        auto cmp=[&](const Point&x,const Point&y){
            return (y-u).toleft(x-u)==1;
        };
        if(cmp(p[0],p.back())){     // 极值在 p[back]
            while(l<r){
                int mid=(l+r)>>1;
                if(cmp(p[r],p[mid]) && cmp(p[mid+1],p[mid]))r=mid;
                else l=mid+1;
            }
        }
        else{       // 极值在 p[0]
            while(l<r){
                int mid=(l+r+1)>>1;
                if(cmp(p[l],p[mid]) && cmp(p[mid-1],p[mid]))l=mid;
                else r=mid-1;
            }
        }
        return l;
    }
};
Convex Andrew(vector<Point>p){
    vector<Point>st;
    Convex ans;
    sort(p.begin(), p.end());
    auto check=[&](const vector<Point>&st,Point u){
        Point tmp1=st.back(),tmp2=*prev(st.end(),2);
        return (tmp1-tmp2).toleft(u-tmp1)<=0;
    };
    for(auto u:p){
        while(st.size()>1 && check(st,u))st.pop_back();
        st.push_back(u);
    }
    int k=st.size();
    p.pop_back();
    reverse(p.begin(), p.end());
    for(auto u:p){
        while(st.size()>k && check(st,u))st.pop_back();
        st.push_back(u);
    }
    st.pop_back();
    ans.p=st;
    return ans;
}

void solve(){
    int n,m;
    cin>>n>>m;
    vector<Point>vec;
    for(int i=1;i<=n;i++){
        int x,y;
        cin>>x>>y;
        vec.emplace_back(x,y);
    }
//    cin>>m;
    Convex con=Andrew(vec);
    vector<Point>p=con.p;
    n=p.size();
    double cir=0,area=0;
    for(int i=0;i<n;i++){
        cir+=p[i].dis(p[(i+1)%n]);
        area+=p[i].cross(p[(i+1)%n]);
    }
    area/=2.0l;
    while(m--){
        int x1,y1,x2,y2;
        cin>>x1>>y1>>x2>>y2;
        Point a((x1+x2)/2.0l,(y1+y2)/2.0l);
        double R=a.dis(Point(x1,y1));
        double ans=R*R/2.0l;
        if(con.is_in(a)){
            cout<<fixed<<setprecision(10)<<ans<<endl;
            continue;
        }
        auto nxt=[&](int x){return x==(n-1)?0:x+1;};
        auto pre=[&](int x){return x==0?(n-1):x-1;};
        int mx=con.find_max(a),mn=con.find_min(a);
        double dis=min(Segment(p[mx],p[nxt(mx)]).dis(a),Segment(p[pre(mn)],p[mn]).dis(a));
        int op1=sgn((p[nxt(mx)]-p[mx]).dot(a-p[mx])),op2=sgn((p[mn]-p[pre(mn)]).dot(a-p[pre(mn)]));
        if(mx!=mn && op1 != op2){
            int l=mx,r=mn-1;
            if(r<l)r+=n;
            while(l<r){
                int mid=(l+r+1)>>1;
                int p1=sgn((p[(mid+1)%n]-p[mid%n]).dot(a-p[mid%n]));
                if(p1==op1)l=mid;
                else r=mid-1;
            }
            l%=n;
            dis=min(dis,Segment(p[l],p[nxt(l)]).dis(a));
        }
        ans+=dis*dis;
        cout<<fixed<<setprecision(10)<<ans<<endl;

//        int mx=con.find_max(a),mn=con.find_min(a);
//        double dis=min(Segment(p[mx],p[nxt(mx)]).dis(a),Segment(p[pre(mn)],p[mn]).dis(a));
//        int op1=sgn((p[nxt(mx)]-p[mx]).cross(a-p[mx])),op2=sgn((p[mn]-p[pre(mn)]).cross(a-p[pre(mn)]));
//        if(mx!=mn && op1 != op2){
//            int l=mx,r=mn-1;
//            if(r<l)r+=n;
//            while(l<r){
//                int mid=(l+r+1)>>1;
//                int p1=sgn((p[(mid+1)%n]-p[mid%n]).cross(a-p[mid%n]));
//                if(p1==op1)l=mid;
//                else r=mid-1;
//            }
//            l%=n;
//            dis=min(dis,Segment(p[l],p[nxt(l)]).dis(a));
//        }

//        double s=cir*dis+pi*dis*dis+area;
//        int t=0;
//        while(s>area){
//            t++;
//            s/=2;
//        }
//        cout<<t<<endl;
    }
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int Te=1;
//    cin>>Te;
    while(Te--){
        solve();
    }
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 3952kb

input:

4 3
0 0
1 0
1 1
0 1
0 0 1 1
1 1 2 2
1 1 2 3

output:

0.2500000000
0.7500000000
1.8750000000

result:

ok Your answer is acceptable!^ ^

Test #2:

score: 0
Accepted
time: 0ms
memory: 4040kb

input:

48 10
-30 0
-29 -4
-28 -7
-27 -9
-25 -12
-22 -16
-21 -17
-17 -20
-14 -22
-12 -23
-9 -24
-5 -25
-4 -25
0 -24
3 -23
5 -22
8 -20
12 -17
13 -16
16 -12
18 -9
19 -7
20 -4
21 0
21 1
20 5
19 8
18 10
16 13
13 17
12 18
8 21
5 23
3 24
0 25
-4 26
-5 26
-9 25
-12 24
-14 23
-17 21
-21 18
-22 17
-25 13
-27 10
-28 ...

output:

589.5000000000
51.4705882353
1051.2500000000
66.6250000000
174.1250000000
562.6750000000
272.3942307692
287.3850000000
689.6250000000
436.2500000000

result:

ok Your answer is acceptable!^ ^

Test #3:

score: 0
Accepted
time: 10ms
memory: 3964kb

input:

5000 5000
-50000000 0
-49999885 -49450
-49999770 -85675
-49999604 -122394
-49999391 -157604
-49999130 -192731
-49998803 -229143
-49998399 -267196
-49997956 -303872
-49997469 -339362
-49996891 -377221
-49996257 -414903
-49995577 -451819
-49994843 -488600
-49994059 -524941
-49993173 -563137
-49992252 ...

output:

2214785369560632.8750000000
1632645104370924.3748779297
3954739966640761.3752441406
5405105667896787.7500000000
817274719687553.0313720703
902260846427661.0824584961
3194363161448624.1250000000
1619744446324385.1248779297
363457485421825.2499694824
4776425533214308.6240234375
8267595460255072.723144...

result:

ok Your answer is acceptable!^ ^

Test #4:

score: 0
Accepted
time: 8ms
memory: 3952kb

input:

2224 5000
-500000 0
-499999 -30
-499998 -59
-499997 -87
-499996 -114
-499995 -140
-499994 -165
-499993 -189
-499992 -212
-499991 -234
-499990 -255
-499989 -275
-499988 -294
-499987 -312
-499986 -329
-499985 -345
-499984 -360
-499982 -389
-499981 -403
-499979 -430
-499978 -443
-499976 -468
-499975 -4...

output:

931340796015.3750000596
410570465847.7500000000
225774975043.7500000000
686588110927.3750000000
803635163394.8750000000
440321806244.7499999702
781364862674.5000000596
303496624306.7500000000
146653887864.7500000000
1361017661096.7500000000
409649028457.5000000000
417747460932.7500000000
46509181005...

result:

ok Your answer is acceptable!^ ^

Test #5:

score: 0
Accepted
time: 3ms
memory: 3956kb

input:

4672 5000
-300 0
-299 -43
-298 -85
-297 -126
-296 -166
-295 -205
-294 -243
-293 -280
-292 -316
-291 -351
-290 -385
-289 -418
-288 -450
-287 -481
-286 -511
-285 -540
-284 -568
-283 -595
-282 -621
-281 -646
-280 -670
-279 -693
-278 -715
-276 -758
-275 -779
-273 -820
-272 -840
-270 -879
-269 -898
-267 ...

output:

356616.5000000000
121018.5000000000
0.2500000000
189.6250000000
103099.6250000000
83253.1250000000
131701.2500000000
58352.5000000000
355863.1250000000
197638.8597240473
605772.4121621622
2062.4458977408
113763.2500000000
134694.5000000000
74679.6520547945
114481.2500000000
60577.2500000000
7456.250...

result:

ok Your answer is acceptable!^ ^

Test #6:

score: 0
Accepted
time: 5ms
memory: 3912kb

input:

576 5000
-300 0
-299 -15
-298 -29
-297 -42
-296 -54
-295 -65
-294 -75
-293 -84
-292 -92
-290 -107
-289 -114
-287 -127
-286 -133
-284 -144
-283 -149
-280 -163
-278 -172
-275 -185
-274 -189
-270 -204
-267 -215
-265 -222
-262 -232
-258 -245
-257 -248
-252 -262
-248 -273
-245 -281
-240 -294
-238 -299
-2...

output:

189295.2500000000
377943.2944162437
299473.0000000000
243821.9171974522
559270.9922279793
100367.5923396675
472743.1250000000
374450.6250000000
77260.6250000000
106891.2307692308
193578.1250000000
98895.0654145078
124020.0000000000
296138.8750000000
1209.1250000000
480040.6250000000
133543.970689655...

result:

ok Your answer is acceptable!^ ^

Test #7:

score: 0
Accepted
time: 4ms
memory: 3868kb

input:

336 5000
-300 0
-299 -11
-298 -21
-297 -30
-296 -38
-295 -45
-294 -51
-292 -62
-291 -67
-289 -76
-288 -80
-285 -91
-283 -98
-280 -108
-279 -111
-275 -122
-272 -130
-270 -135
-267 -142
-263 -151
-258 -162
-257 -164
-251 -175
-246 -184
-242 -191
-239 -196
-234 -204
-227 -215
-225 -218
-218 -228
-213 -...

output:

478.1250000000
408.1250000000
1341.2500000000
861.2500000000
4210.0000000000
1709.1250000000
846.2500000000
1389.1250000000
722.5000000000
753.1250000000
574.2500000000
1167.1250000000
439.6250000000
5650.2500000000
619.6250000000
2664.5000000000
2138.6250000000
2138.6250000000
1226.2500000000
1226....

result:

ok Your answer is acceptable!^ ^

Test #8:

score: 0
Accepted
time: 5ms
memory: 4016kb

input:

336 5000
-300 0
-299 -11
-298 -21
-297 -30
-296 -38
-295 -45
-294 -51
-292 -62
-291 -67
-289 -76
-288 -80
-285 -91
-283 -98
-280 -108
-279 -111
-275 -122
-272 -130
-270 -135
-267 -142
-263 -151
-258 -162
-257 -164
-251 -175
-246 -184
-242 -191
-239 -196
-234 -204
-227 -215
-225 -218
-218 -228
-213 -...

output:

95.1250000000
8382.6250000000
77361.1250000000
142408.1250000000
98056.2500000000
110581.2500000000
20413.0000000000
1253.1250000000
64468.6250000000
8915.6250000000
93179.1250000000
26286.2500000000
35118.2500000000
129681.2500000000
59545.6250000000
49997.9103773585
1685.1250000000
58020.625000000...

result:

ok Your answer is acceptable!^ ^

Test #9:

score: 0
Accepted
time: 10ms
memory: 3896kb

input:

5000 5000
-50000000 0
-49999912 -33572
-49999824 -59400
-49999710 -83347
-49999578 -105149
-49999382 -130924
-49999166 -154591
-49998916 -178069
-49998599 -203894
-49998262 -228398
-49997905 -251647
-49997466 -277451
-49997003 -302413
-49996511 -326907
-49995964 -352128
-49995393 -376671
-49994795 -...

output:

481990667522174063.0000000000
900047257776892012.9375000000
84250235108292086.0468750000
357963472278544291.7500000000
758024710210129399.3750000000
651805790712522724.3750000000
422072215223185896.7500000000
571948904059660677.3437500000
685946954834850006.6875000000
781017527404628198.5000000000
3...

result:

ok Your answer is acceptable!^ ^

Test #10:

score: 0
Accepted
time: 10ms
memory: 3964kb

input:

5000 5000
-50000000 0
-49999762 -138397
-49999461 -244153
-49999007 -349713
-49998392 -456086
-49997577 -566637
-49996632 -673023
-49995462 -784273
-49994137 -894156
-49992625 -1005080
-49990945 -1115094
-49989066 -1226720
-49987021 -1337531
-49984788 -1449227
-49982415 -1559155
-49979887 -1668061
-...

output:

259053256470500481.8437500000
472297859897907116.8750000000
271976522374482758.8750000000
930648882061706004.8750000000
110596174224097027.8750000000
385963660067947077.5000000000
441658538323309453.6562500000
259108189662189395.8750000000
379723545376251013.7187500000
43293951022380795.8710937500
2...

result:

ok Your answer is acceptable!^ ^

Extra Test:

score: 0
Extra Test Passed