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답안 #273864

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
273864 2020-08-19T07:40:38 Z 최은수(#5105) Mountains and Valleys (CCO20_day1problem3) C++17
3 / 25
 46 ms 46456 KB 
#include<iostream>
#include<vector>
#include<algorithm>
#define ep emplace
#define eb emplace_back
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
using namespace std;
typedef long long ll;
typedef pair<int,int>pi;
typedef pair<ll,ll>pl;
const int inf=1e9+7;
const ll INF=1e18;
struct max4
{
    int a,b,c,d;
    max4(){a=b=c=d=0;}
    inline void upd(int x)
    {
        if(x>a)
            d=c,c=b,b=a,a=x;
        else if(x>b)
            d=c,c=b,b=x;
        else if(x>c)
            d=c,c=x;
        else if(x>d)
            d=x;
        return;
    }
    inline int get()
    {
        return a;
    }
    inline int get(int x)
    {
        return x==a?b:a;
    }
    inline int get(int x,int y)
    {
        if(x<y)
            swap(x,y);
        return x==a?(y==b?c:b):(y==a?b:a);
    }
    inline int get(int x,int y,int z)
    {
        if(x<y)
            swap(x,y);
        if(x<z)
            swap(x,z);
        if(y<z)
            swap(y,z);
        return x==a?(y==b?(z==c?d:c):(z==b?c:b)):(y==a?(z==b?c:b):(z==a?b:a));
    }
};
vector<int>adj[500010];
int depth[500010];
void ddfs(int x,int p)
{
    depth[x]=depth[p]+1;
    for(int&t:adj[x])
        if(t!=p)
            ddfs(t,x);
    return;
}
int dep[500010];
int spa[500010][19];
inline int kpa(int x,int k)
{
    for(;k>0;k^=k&-k)
        x=spa[x][__builtin_ctz(k)];
    return x;
}
inline int lca(int x,int y)
{
    if(dep[x]>dep[y])
        x=kpa(x,dep[x]-dep[y]);
    else
        y=kpa(y,dep[y]-dep[x]);
    if(x==y)
        return x;
    for(int i=19;i-->0;)
        if(spa[x][i]!=spa[y][i])
            x=spa[x][i],y=spa[y][i];
    return spa[x][0];
}
max4 dp1[500010],dp2[500010];
max4 dp3[500010],dp4[500010];
void sdfs(int x,int p)
{
    spa[x][0]=p;
    for(int i=0;i<18;i++)
        spa[x][i+1]=spa[spa[x][i]][i];
    dep[x]=dep[p]+1;
    for(int&t:adj[x])
        if(t!=p)
            sdfs(t,x),dp1[x].upd(dp1[t].get()+1),
            dp2[x].upd(max(dp2[t].get(),dp1[t].get()+dp1[t].get(dp1[t].get())));
    dp3[x]=dp1[x];
    dp4[x]=dp2[x];
    return;
}
int child[500010][19];
int spd[500010][19];
int dpth(int x,int k)
{
    int ret=max({dp2[x].get(),dp1[x].get()+dp1[x].get(dp1[x].get())});
    bool chk=0;
    int y=x;
    while(k>0)
    {
        int i=__builtin_ctz(k);
        k^=k&-k;
        if(!chk)
        {
            chk=1;
            ret=max(ret,spd[x][i]);
            y=child[x][i];
            x=spa[x][i];
            continue;
        }
        {
            int fc1=dp1[y].get()+1;
            int fc2=max(dp2[y].get(),dp1[y].get()+dp1[y].get(dp1[y].get()));
            ret=max({ret,spd[x][i],dp2[x].get(fc2),
            dp1[x].get(fc1)+dp1[x].get(dp1[x].get(fc1),fc1)});
        }
        y=child[x][i];
        x=spa[x][i];
    }
    return ret;
}
int cm[500010][19];
pi cut[500010][19];
pair<pi,int>pth(int x,int k)
{
    pair<pi,int>ret;
    ret.fi.fi=ret.fi.se=dp1[x].get();
    int len=0;
    int y=x;
    while(k>0)
    {
        int i=__builtin_ctz(k);
        k^=k&-k;
        if(len==0)
        {
            len=1<<i;
            ret.se=max(cm[x][i],ret.fi.fi+cut[x][i].se);
            ret.fi.fi=max(ret.fi.fi,cut[x][i].fi);
            ret.fi.se=max(ret.fi.se+len,cut[x][i].se);
            y=child[x][i];
            x=spa[x][i];
            continue;
        }
        {
            pi c1=ret.fi;
            pi c2=cut[x][i];
            int cur=dp1[x].get(dp1[y].get()+1);
            ret.se=max({ret.se+(1<<i),cm[x][i]+len,
            c1.fi+c2.se,c1.fi+cur+(1<<i),c2.se+cur+len});
            ret.fi.fi=max({c1.fi,c2.fi+len,cur+len});
            ret.fi.se=max({c2.se,c1.se+(1<<i),cur+(1<<i)});
        }
        len+=1<<i;
        y=child[x][i];
        x=spa[x][i];
    }
    return ret;
}
void dfs2(int x,int p)
{
    spd[x][0]=cm[x][0]=cut[x][0].fi=cut[x][0].se=0;
    for(int i=0,y=x;i<18;y=spa[y][i++])
    {
        if(spa[x][i]==0)
            break;
        child[x][i]=y;
        {
            int fc1=dp1[y].get()+1;
            int fc2=max(dp2[y].get(),dp1[y].get()+dp1[y].get(dp1[y].get()));
            spd[x][i+1]=max({spd[x][i],spd[spa[x][i]][i],dp2[spa[x][i]].get(fc2),
            dp1[spa[x][i]].get(fc1)+dp1[spa[x][i]].get(dp1[spa[x][i]].get(fc1),fc1)});
        }
        {
            pi c1=cut[x][i];
            pi c2=cut[spa[x][i]][i];
            int cur=dp1[spa[x][i]].get(dp1[y].get()+1);
            cm[x][i+1]=max({cm[x][i]+(1<<i),cm[spa[x][i]][i]+(1<<i),
            c1.fi+c2.se,c1.fi+cur+(1<<i),c2.se+cur+(1<<i)});
            cut[x][i+1].fi=max({c1.fi,c2.fi+(1<<i),cur+(1<<i)});
            cut[x][i+1].se=max({c2.se,c1.se+(1<<i),cur+(1<<i)});
        }
    }
    for(int&t:adj[x])
    {
        if(t!=p)
        {
            int mx=dp3[x].get(dp1[t].get()+1);
            dp3[t].upd(mx+1);
            int mx2=dp3[x].get(mx,dp1[t].get()+1);
            int td2=max(dp1[t].get(),dp1[t].get()+dp1[t].get(dp1[t].get()));
            dp4[t].upd(max(dp4[x].get(td2),mx+mx2));
            dfs2(t,x);
        }
    }
    return;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n,m;
    cin>>n>>m;
    vector<pair<pi,int> >ev;
    for(int i=0;i<m;i++)
    {
        int u,v,w;
        cin>>u>>v>>w;
        u++,v++;
        if(w==1)
            adj[u].eb(v),adj[v].eb(u);
        else if(w*2<n)
            ev.eb(pi(u,v),w);
    }
    sdfs(1,0);
    int ans=inf;
    {
        int d1=max_element(dep+1,dep+n+1)-dep;
        ddfs(d1,0);
        ans=2*n-1-*max_element(depth+1,depth+n+1);
    }
    dfs2(1,0);
    for(auto&t:ev)
    {
        int u=t.fi.fi;
        int v=t.fi.se;
        int w=t.se;
        int l=lca(u,v);
        int len=dep[u]+dep[v]-dep[l]*2;
        int dmax=0,cmax=0;
        if(v==l)
            swap(u,v);
        if(u==l)
        {
            auto q1=dpth(v,dep[v]-dep[l]);
            auto q2=pth(v,dep[v]-dep[l]);
            int y=kpa(v,dep[v]-dep[l]-1);
            {
                int fc1=dp1[y].get()+1;
                int fc2=max(dp2[y].get(),dp1[y].get()+dp1[y].get(dp1[y].get()));
                dmax=max({q1,dp4[l].get(fc2),
                dp3[l].get(fc1)+dp3[l].get(dp3[l].get(fc1),fc1)});
            }
            {
                int cur=dp3[l].get(dp1[y].get()+1);
                cmax=max(q2.se,q2.fi.fi+cur);
            }
        }
        else
        {
            int qu1=dpth(u,dep[u]-dep[l]);
            int qv1=dpth(v,dep[v]-dep[l]);
            auto qu2=pth(u,dep[u]-dep[l]);
            auto qv2=pth(v,dep[v]-dep[l]);
            int yu=kpa(u,dep[u]-dep[l]-1);
            int yv=kpa(v,dep[v]-dep[l]-1);
            {
                int fcu1=dp1[yu].get()+1;
                int fcu2=max(dp2[yu].get(),dp1[yu].get()+dp1[yu].get(dp1[yu].get()));
                int fcv1=dp1[yv].get()+1;
                int fcv2=max(dp2[yv].get(),dp1[yv].get()+dp1[yv].get(dp1[yv].get()));
                dmax=max({qu1,qv1,dp4[l].get(fcu2,fcv2),
                dp3[l].get(fcu1,fcv1)+dp3[l].get(dp3[l].get(fcu1,fcv1),fcu1,fcv1)});
            }
            {
                int cur=dp3[l].get(dp1[yu].get()+1,dp1[yv].get()+1);
                cmax=max({qu2.se,qv2.se,qu2.fi.fi+qv2.fi.fi,
                qu2.fi.fi+cur+(dep[v]-dep[l]),qv2.fi.fi+cur+(dep[u]-dep[l])});
            }
        }
        ans=min(ans,n*2-2-dmax-len+w);
        ans=min(ans,n*2-4-cmax+w);
    }
    cout<<ans<<endl;
    return 0;
}

Subtask #1
1.0 / 1.0

# 결과 실행 시간 메모리 Grader output
1 Correct 29 ms 43392 KB Output is correct
2 Correct 29 ms 43392 KB Output is correct
3 Correct 29 ms 43384 KB Output is correct
4 Correct 29 ms 43392 KB Output is correct
5 Correct 30 ms 43392 KB Output is correct
6 Correct 28 ms 43428 KB Output is correct
7 Correct 28 ms 43392 KB Output is correct
8 Correct 29 ms 43392 KB Output is correct
9 Correct 28 ms 43392 KB Output is correct
10 Correct 28 ms 43384 KB Output is correct
11 Correct 29 ms 43392 KB Output is correct
12 Correct 28 ms 43388 KB Output is correct
13 Correct 28 ms 43384 KB Output is correct
14 Correct 29 ms 43392 KB Output is correct
15 Correct 28 ms 43392 KB Output is correct

Subtask #2
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 29 ms 43392 KB Output is correct
2 Correct 29 ms 43392 KB Output is correct
3 Correct 29 ms 43384 KB Output is correct
4 Correct 29 ms 43392 KB Output is correct
5 Correct 30 ms 43392 KB Output is correct
6 Correct 28 ms 43428 KB Output is correct
7 Correct 28 ms 43392 KB Output is correct
8 Correct 29 ms 43392 KB Output is correct
9 Correct 28 ms 43392 KB Output is correct
10 Correct 28 ms 43384 KB Output is correct
11 Correct 29 ms 43392 KB Output is correct
12 Correct 28 ms 43388 KB Output is correct
13 Correct 28 ms 43384 KB Output is correct
14 Correct 29 ms 43392 KB Output is correct
15 Correct 28 ms 43392 KB Output is correct
16 Correct 29 ms 43392 KB Output is correct
17 Correct 31 ms 43392 KB Output is correct
18 Correct 29 ms 43392 KB Output is correct
19 Correct 29 ms 43392 KB Output is correct
20 Correct 30 ms 43392 KB Output is correct
21 Incorrect 30 ms 43404 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
2.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 36 ms 46328 KB Output is correct
2 Correct 41 ms 46456 KB Output is correct
3 Correct 37 ms 46208 KB Output is correct
4 Correct 38 ms 46072 KB Output is correct
5 Correct 36 ms 46072 KB Output is correct
6 Correct 38 ms 45816 KB Output is correct
7 Correct 46 ms 46336 KB Output is correct
8 Correct 37 ms 46208 KB Output is correct
9 Correct 38 ms 46336 KB Output is correct
10 Correct 38 ms 46072 KB Output is correct
11 Correct 35 ms 46208 KB Output is correct
12 Correct 39 ms 45952 KB Output is correct
13 Correct 46 ms 46072 KB Output is correct
14 Correct 43 ms 46072 KB Output is correct

Subtask #4
0.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 29 ms 43392 KB Output is correct
2 Correct 29 ms 43392 KB Output is correct
3 Correct 29 ms 43384 KB Output is correct
4 Correct 29 ms 43392 KB Output is correct
5 Correct 30 ms 43392 KB Output is correct
6 Correct 28 ms 43428 KB Output is correct
7 Correct 28 ms 43392 KB Output is correct
8 Correct 29 ms 43392 KB Output is correct
9 Correct 28 ms 43392 KB Output is correct
10 Correct 28 ms 43384 KB Output is correct
11 Correct 29 ms 43392 KB Output is correct
12 Correct 28 ms 43388 KB Output is correct
13 Correct 28 ms 43384 KB Output is correct
14 Correct 29 ms 43392 KB Output is correct
15 Correct 28 ms 43392 KB Output is correct
16 Correct 29 ms 43392 KB Output is correct
17 Correct 31 ms 43392 KB Output is correct
18 Correct 29 ms 43392 KB Output is correct
19 Correct 29 ms 43392 KB Output is correct
20 Correct 30 ms 43392 KB Output is correct
21 Incorrect 30 ms 43404 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #5
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 29 ms 43392 KB Output is correct
2 Correct 29 ms 43392 KB Output is correct
3 Correct 29 ms 43384 KB Output is correct
4 Correct 29 ms 43392 KB Output is correct
5 Correct 30 ms 43392 KB Output is correct
6 Correct 28 ms 43428 KB Output is correct
7 Correct 28 ms 43392 KB Output is correct
8 Correct 29 ms 43392 KB Output is correct
9 Correct 28 ms 43392 KB Output is correct
10 Correct 28 ms 43384 KB Output is correct
11 Correct 29 ms 43392 KB Output is correct
12 Correct 28 ms 43388 KB Output is correct
13 Correct 28 ms 43384 KB Output is correct
14 Correct 29 ms 43392 KB Output is correct
15 Correct 28 ms 43392 KB Output is correct
16 Correct 29 ms 43392 KB Output is correct
17 Correct 31 ms 43392 KB Output is correct
18 Correct 29 ms 43392 KB Output is correct
19 Correct 29 ms 43392 KB Output is correct
20 Correct 30 ms 43392 KB Output is correct
21 Incorrect 30 ms 43404 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #6
0.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 29 ms 43392 KB Output is correct
2 Correct 29 ms 43392 KB Output is correct
3 Correct 29 ms 43384 KB Output is correct
4 Correct 29 ms 43392 KB Output is correct
5 Correct 30 ms 43392 KB Output is correct
6 Correct 28 ms 43428 KB Output is correct
7 Correct 28 ms 43392 KB Output is correct
8 Correct 29 ms 43392 KB Output is correct
9 Correct 28 ms 43392 KB Output is correct
10 Correct 28 ms 43384 KB Output is correct
11 Correct 29 ms 43392 KB Output is correct
12 Correct 28 ms 43388 KB Output is correct
13 Correct 28 ms 43384 KB Output is correct
14 Correct 29 ms 43392 KB Output is correct
15 Correct 28 ms 43392 KB Output is correct
16 Correct 29 ms 43392 KB Output is correct
17 Correct 31 ms 43392 KB Output is correct
18 Correct 29 ms 43392 KB Output is correct
19 Correct 29 ms 43392 KB Output is correct
20 Correct 30 ms 43392 KB Output is correct
21 Incorrect 30 ms 43404 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #7
0.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 29 ms 43392 KB Output is correct
2 Correct 29 ms 43392 KB Output is correct
3 Correct 29 ms 43384 KB Output is correct
4 Correct 29 ms 43392 KB Output is correct
5 Correct 30 ms 43392 KB Output is correct
6 Correct 28 ms 43428 KB Output is correct
7 Correct 28 ms 43392 KB Output is correct
8 Correct 29 ms 43392 KB Output is correct
9 Correct 28 ms 43392 KB Output is correct
10 Correct 28 ms 43384 KB Output is correct
11 Correct 29 ms 43392 KB Output is correct
12 Correct 28 ms 43388 KB Output is correct
13 Correct 28 ms 43384 KB Output is correct
14 Correct 29 ms 43392 KB Output is correct
15 Correct 28 ms 43392 KB Output is correct
16 Correct 29 ms 43392 KB Output is correct
17 Correct 31 ms 43392 KB Output is correct
18 Correct 29 ms 43392 KB Output is correct
19 Correct 29 ms 43392 KB Output is correct
20 Correct 30 ms 43392 KB Output is correct
21 Incorrect 30 ms 43404 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #8
0.0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Correct 29 ms 43392 KB Output is correct
2 Correct 29 ms 43392 KB Output is correct
3 Correct 29 ms 43384 KB Output is correct
4 Correct 29 ms 43392 KB Output is correct
5 Correct 30 ms 43392 KB Output is correct
6 Correct 28 ms 43428 KB Output is correct
7 Correct 28 ms 43392 KB Output is correct
8 Correct 29 ms 43392 KB Output is correct
9 Correct 28 ms 43392 KB Output is correct
10 Correct 28 ms 43384 KB Output is correct
11 Correct 29 ms 43392 KB Output is correct
12 Correct 28 ms 43388 KB Output is correct
13 Correct 28 ms 43384 KB Output is correct
14 Correct 29 ms 43392 KB Output is correct
15 Correct 28 ms 43392 KB Output is correct
16 Correct 29 ms 43392 KB Output is correct
17 Correct 31 ms 43392 KB Output is correct
18 Correct 29 ms 43392 KB Output is correct
19 Correct 29 ms 43392 KB Output is correct
20 Correct 30 ms 43392 KB Output is correct
21 Incorrect 30 ms 43404 KB Output isn't correct
22 Halted 0 ms 0 KB -