Submission #428160

#	Time	Username	Problem	Language	Result	Execution time	Memory
428160		juggernaut	Capital City (JOI20_capital_city)	C++17	11 / 100	3089 ms	86188 KiB

capital_city

#include<bits/stdc++.h>
#define fr first
#define sc second
using namespace std;
void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
typedef long long ll;
#define USING_ORDERED_SET 0
#if USING_ORDERED_SET
#include<bits/extc++.h>
using namespace __gnu_pbds;
template<class T>using ordered_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
#endif
template<class T>void umax(T &a,T b){if(a<b)a=b;}
template<class T>void umin(T &a,T b){if(b<a)a=b;}
#ifdef IOI2021SG
    #define printl(args...)printf(args)
#else
    #define printl(args...)((void)0)
#endif
int n,k;
int tin[200005],tout[200005],timer,up[200005][18];
vector<int>g[200005],color[200005],g1[200005],g2[200005];
int a[200005];
void dfs(int v,int p){
    tin[v]=++timer;
    up[v][0]=p;
    for(int i=1;i<18;i++)up[v][i]=up[up[v][i-1]][i-1];
    for(int to:g[v])if(to!=p)dfs(to,v);
    tout[v]=++timer;
}
bool upper(int a,int b){
    return tin[a]<=tin[b]&&tout[a]>=tout[b];
}
int lca(int a,int b){
    if(upper(a,b))return a;
    if(upper(b,a))return b;
    for(int i=17;i>=0;i--)if(!upper(up[a][i],b))a=up[a][i];
    return up[a][0];
}
int lca(vector<int>&vec){
    int l=vec[0];
    for(int i=1;i<(int)vec.size();i++)l=lca(l,vec[i]);
    return l;
}
unordered_map<int,bool>vs[200005];
vector<pair<int,int>>edges;
void add_edge(int a,int b){
    if(a^b){
        if(vs[a][b])return;
        vs[a][b]=true;
        edges.emplace_back(a,b);
        g1[a].push_back(b);
        g2[b].push_back(a);
    }
}
void add(int v,int a,int l){
    while(a!=l){
        a=up[a][0];
        add_edge(v,::a[a]);
        if(v^::a[a])break;
    }
}
int cnt=0;
bool vis[200005];
void run(int v){
    vis[v]=true;
    cnt++;
    for(int to:g1[v])if(!vis[to])run(to);
}
int main(){
    scanf("%d%d",&n,&k);
    for(int i=1;i<n;i++){
        int x,y;
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for(int i=1;i<=n;i++){
        scanf("%d",&a[i]);
        color[a[i]].push_back(i);
    }
    dfs(1,1);
    for(int i=1;i<=k;i++){
        int l=lca(color[i]);
        for(int j=0;j<(int)color[i].size();j++)add(i,color[i][j],l);
    }
    int ans=k;
    for(int i=1;i<=k;i++){
        for(int j=1;j<=k;j++)vis[j]=false;
        cnt=0;
        run(i);
        umin(ans,cnt);
    }
    printf("%d",ans-1);
}

Compilation message (stderr)

capital_city.cpp: In function 'void usaco(std::string)':
capital_city.cpp:5:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
capital_city.cpp:5:66: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                                                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
capital_city.cpp: In function 'int main()':
capital_city.cpp:71:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |     scanf("%d%d",&n,&k);
      |     ~~~~~^~~~~~~~~~~~~~
capital_city.cpp:74:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         scanf("%d%d",&x,&y);
      |         ~~~~~^~~~~~~~~~~~~~
capital_city.cpp:79:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |         scanf("%d",&a[i]);
      |         ~~~~~^~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 59