Submission #1174651

#	Time	Username	Problem	Language	Result	Execution time	Memory
1174651		guagua0407	Balanced Tree (info1cup18_balancedtree)	C++20	0 / 100	4093 ms	9488 KiB

balancedtree

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

const int inf=1e9;

void solve(){
    int n;
    cin>>n;
    vector<vector<int>> adj(n+1);
    for(int i=0;i<n-1;i++){
        int a,b;
        cin>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    vector<int> C(n+1);
    for(int i=1;i<=n;i++){
        cin>>C[i];
    }
    pair<int,vector<int>> mn;
    mn.f=inf;
    for(int S=0;S<(1<<n);S++){
        vector<int> c(n+1);
        for(int i=0;i<n;i++){
            if(C[i+1]!=-1) c[i+1]=C[i+1];
            else if(S&(1<<i)) c[i+1]=1;
            else c[i+1]=0;
        }
        int l=0,r=n+1;
        while(l<r){
            int D=(l+r)/2;
            //cout<<D<<'\n';
            vector<vector<int>> mn(n+1,vector<int>(2));
            vector<vector<int>> cand(n+1,vector<int>(2));
            vector<int> d(n+1);
            function<void(int,int)> dfs=[&](int v,int p){
                d[v]=d[p]+1;
                for(auto u:adj[v]){
                    if(u==p) continue;
                    dfs(u,v);
                }
                mn[v][0]=mn[v][1]=inf;
                mn[v][c[v]]=d[v];
                for(auto u:adj[v]){
                    if(u==p) continue;
                    for(int t=0;t<2;t++){
                        if(cand[u][t]!=-1){
                            if(cand[u][t]+mn[v][t]-2*d[v]<=D) cand[u][t]=-1;
                        }
                        mn[v][t]=min(mn[v][t],mn[u][t]);
                    }
                }
                mn[v][0]=mn[v][1]=inf;
                mn[v][c[v]]=d[v];
                reverse(all(adj[v]));
                for(auto u:adj[v]){
                    if(u==p) continue;
                    for(int t=0;t<2;t++){
                        if(cand[u][t]!=-1){
                            if(cand[u][t]+mn[v][t]-2*d[v]<=D) cand[u][t]=-1;
                        }
                        mn[v][t]=min(mn[v][t],mn[u][t]);
                    }
                }
                mn[v][c[v]]=inf;
                for(auto u:adj[v]){
                    if(u==p) continue;
                    mn[v][c[v]]=min(mn[v][c[v]],mn[u][c[v]]);
                }
                cand[v][0]=cand[v][1]=-1;
                if(mn[v][c[v]]-d[v]>D) cand[v][c[v]]=d[v];
                mn[v][c[v]]=min(mn[v][c[v]],d[v]);
                for(auto u:adj[v]){
                    if(u==p) continue;
                    for(int t=0;t<2;t++){
                        cand[v][t]=max(cand[v][t],cand[u][t]);
                    }
                }
                //cout<<v<<' '<<cand[v][0]<<' '<<cand[v][1]<<'\n';
            };
            dfs(1,0);
            if(cand[1][0]==-1 and cand[1][1]==-1){
                r=D;
            }
            else{
                l=D+1;
            }
        }
        mn=min(mn,{l,c});
    }
    if(mn.f==n+1){
        cout<<-1<<'\n';
    }
    else{
        cout<<mn.f<<'\n';
        for(int i=1;i<=n;i++){
            cout<<mn.s[i]<<' ';
        }
        cout<<'\n';
    }
}

int main() {_
    int t;
    cin>>t;
    while(t--){
        solve();
    }
    return 0;
}
//maybe its multiset not set
//yeeorz
//diaoborz

Compilation message (stderr)

balancedtree.cpp: In function 'void setIO(std::string)':
balancedtree.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
balancedtree.cpp:16:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 26
• Subtask 4: 0 / 45
• Subtask 5: 0 / 6