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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#227739#6559. A Tree and Two EdgesNerovix#WA 24ms10244kbC++205.5kb2023-10-27 22:25:332023-10-27 22:25:34

Judging History

你现在查看的是最新测评结果

  • [2023-10-27 22:25:34]
  • 评测
  • 测评结果:WA
  • 用时:24ms
  • 内存:10244kb
  • [2023-10-27 22:25:33]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define mpr make_pair
#define db double
#define ll long long

const int maxn=5e4+10;
int n,q;
vector<int>v[maxn];
int f[maxn];
int getf(int x){
    return x==f[x]?x:(f[x]=getf(f[x]));
}
int a1,b1;
int a2,b2;
int fa[maxn];
int de[maxn];
void dfs1(int x){
    de[x]=de[fa[x]]+1;
    for(int y:v[x]){
        if(y==fa[x])continue;
        fa[y]=x;
        dfs1(y);
    }
}
map<pair<int,int>,int>ty;
void insty(int x,int y,int t){
    // cout<<x<<" "<<y<<" "<<t<<" insty\n";
    ty[mpr(min(x,y),max(x,y))]|=t;
    
}
int getty(int x,int y){
    return ty[mpr(min(x,y),max(x,y))];
}
void jumpandtag(int x,int y,int t){
    // cout<<x<<" "<<y<<" "<<t<<"\n";
    if(de[x]<de[y])swap(x,y);
    while(de[x]>de[y]){
        insty(x,fa[x],t);
        x=fa[x];
    }
    while(x!=y){
        insty(x,fa[x],t);
        insty(y,fa[y],t);
        x=fa[x],y=fa[y];
    }
    return;
}
int nodety[maxn];
int rt[maxn];
int dfsfind2(int x,int fa){
    for(int y:v[x]){
        if(y==fa)continue;
        int tmp=getty(x,y);
        if(tmp==1)continue;
        if(tmp==2)return 1;
        if(dfsfind2(y,x))return 1;
    }
    return 0;
}
void dfstag0(int x,int r){
    nodety[x]=0;
    rt[x]=r;
    for(int y:v[x]){
        if(nodety[y]!=-1)continue;
        if(getty(x,y)==0){
            dfstag0(y,r);
        }
    }
}
void dfstag1(int x,int r){
    nodety[x]=1;
    rt[x]=r;
    for(int y:v[x]){
        if(nodety[y]!=-1)continue;
        if(getty(x,y)==0){
            dfstag1(y,r);
        }
    }
}
void dfstag2(int x,int r){
    nodety[x]=2;
    rt[x]=r;
    for(int y:v[x]){
        if(nodety[y]!=-1)continue;
        if(getty(x,y)==0){
            dfstag2(y,r);
        }
    }
}
void solve0(){
    // cerr<<"solve ty0\n";
    memset(nodety,-1,sizeof nodety);
    for(int i=1;i<=n;i++){
        int ok=0;
        for(int j:v[i]){
            if(getty(i,j)==1)ok=1;
            // cout<<i<<" "<<j<<" "<<getty(i,j)<<"\n";
        }
        if(ok){
            int u=dfsfind2(i,0);
            if(u==1){
                // cout<<i<<" 0\n";
                dfstag0(i,i);
            }
            else{
                // cout<<i<<" 1\n";

                dfstag1(i,i);
            }
        }
    }
    for(int i=1;i<=n;i++){
        int ok=0;
        for(int j:v[i]){
            if(getty(i,j)==2)ok=1;
        }
        if(ok){
            if(nodety[i]==-1){
                dfstag2(i,i);
            }
        }
    }
    // for(int i=1;i<=n;i++){
    //     cout<<nodety[i]<<" \n"[i==n];
    // }
    for(int i=1;i<=q;i++){
        int a,b;
        cin>>a>>b;
        int aa=a,bb=b;
        a=nodety[a];
        b=nodety[b];
        if(a>b)swap(a,b);
        if(a==0&&b==0)cout<<"1\n";
        else if(a==0)cout<<"2\n";
        else if(a==b){
            if(rt[aa]==rt[bb])cout<<"1\n";
            else cout<<"2\n";
        }
        else cout<<"4\n";
    }
    return;
}
void dfstag(int x,int t,int r){
    nodety[x]=t;
    rt[x]=r;
    for(int y:v[x]){
        if(nodety[y]!=-1)continue;
        if(getty(x,y)==0){
            dfstag(y,t,r);
        }
    }
}
void solve1(){
    // cerr<<"solve ty1\n";
    int ty=3;
    for(int i=1;i<=n;i++){
        int h1=0,h2=0,h3=0;
        for(int j:v[i]){
            int tmp=getty(i,j);
            if(tmp==1){
                h1=1;
            }
            if(tmp==2)h2=1;
            if(tmp==3)h3=1;
        }
        if(h1+h2+h3==3){
            ++ty;
            dfstag(i,ty,i);
        }
        else{
            if(h1){
                dfstag(i,1,i);
            }
            else if(h2){
                dfstag(i,2,i);
            }
            else if(h3){
                dfstag(i,3,i);
            }
        }
    }
    for(int i=1;i<=q;i++){
        int a,b;
        cin>>a>>b;
        int aa=a,bb=b;
        a=nodety[a];
        b=nodety[b];
        if(a>b)swap(a,b);
        if(a<=3&&b<=3){
            if(a==b){
                if(rt[aa]==rt[bb])cout<<"1\n";
                else cout<<"3\n";
            }
            else{
                cout<<"4\n";
            }
        }
        else{
            if(a<=3){
                cout<<"3\n";
            }
            else{
                if(a==b){
                    if(rt[aa]==rt[bb]){
                        cout<<"1\n";
                    }
                    else assert(0);
                }
                else{
                    cout<<"3\n";
                }
            }
        }
    }
}
void solve(){
    cin>>n>>q;
    for(int i=1;i<=n;i++)f[i]=i;
    for(int i=1;i<=n+1;i++){
        int a,b;
        cin>>a>>b;
        if(getf(a)!=getf(b)){
            v[a].pb(b);
            v[b].pb(a);
            f[getf(a)]=getf(b);
        }
        else{
            if(!a1){
                a1=a,b1=b;
            }
            else{
                a2=a,b2=b;
            }
        }
    }
    dfs1(1);
    v[a1].pb(b1);
    v[b1].pb(a1);
    v[a2].pb(b2);
    v[b2].pb(a2);
    insty(a1,b1,1);
    insty(a2,b2,2);
    jumpandtag(a1,b1,1);
    jumpandtag(a2,b2,2);
    int tty=0;
    for(auto p:ty){
        if(p.se==3)tty=1;
    }
    if(tty)solve1();
    else solve0();
}
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    int t=1;
    // cin>>t;
    while(t--){
        solve();
    }
    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 5796kb

input:

4 6
1 2
1 3
1 4
2 3
2 4
1 2
1 3
1 4
2 3
2 4
3 4

output:

3
3
3
3
3
4

result:

ok 6 lines

Test #2:

score: 0
Accepted
time: 1ms
memory: 5116kb

input:

6 4
1 2
1 3
1 6
2 3
3 4
3 5
4 5
1 2
1 3
1 4
1 6

output:

2
2
4
1

result:

ok 4 lines

Test #3:

score: -100
Wrong Answer
time: 24ms
memory: 10244kb

input:

50000 50000
11561 23122
14261 28523
24407 48814
17947 35894
14803 29607
19557 39115
12415 24830
9583 19167
18397 36794
439 878
18040 36080
17150 34300
7922 15845
18938 37877
18625 37250
6459 12919
9818 19636
3579 7158
21323 42646
23882 47764
13603 27207
8353 16707
15907 31814
20935 41871
11686 23372...

output:

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
...

result:

wrong answer 1st lines differ - expected: '4', found: '1'