Submission #1174650

#	Time	Username	Problem	Language	Result	Execution time	Memory
1174650		guagua0407	Balanced Tree (info1cup18_balancedtree)	C++20	13 / 100	325 ms	9236 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];
    }
    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;
        }
    }
    if(l==n+1){
        cout<<-1<<'\n';
    }
    else{
        cout<<l<<'\n';
        for(int i=1;i<=n;i++){
            cout<<c[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: 13 / 13
• Subtask 3: 0 / 26
• Subtask 4: 0 / 45
• Subtask 5: 0 / 6