Submission #589312

#	Time	Username	Problem	Language	Result	Execution time	Memory
589312		jasmin	Wells (CEOI21_wells)	C++17	0 / 100	1 ms	340 KiB

wells

#include<bits/stdc++.h>
using namespace std;
#define int long long 
 
struct graph{
    vector<vector<int> > adi;
    vector<int> depth;
 
    graph(int n){
        adi.resize(n);
        depth.resize(n);
    }
 
    bool dfs(int v, int p, int k, int d){
 
        bool pos=true;
        int dist1=0;
        int dist2=0;
        for(auto u: adi[v]){
            if(u==p) continue;
 
            pos=pos && dfs(u, v, k, (d+1)%k);
            
            if(depth[u]>dist1){
                dist2=dist1;
                dist1=depth[u];
            }
            else{
                dist2=max(dist2, depth[u]);
            }
        }

        if(adi[v].size()>2 && d!=0){

            if(2*(k-d)+1<=k && dist1>=(k-d) && dist2>=(k-d)){
                pos=false;
            }

            if(min(k-d-1, dist1)+min(k-d-1, dist2)+1>=k){
                pos=false;
            }
        }
 
        depth[v]=dist1+1;
        return pos;
    }
};
 
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
 
    int n, k;
    cin >> n >> k;
    graph g(n);
    for(int i=0; i<n-1; i++){
        int a, b;
        cin >> a >> b;
        g.adi[a-1].push_back(b-1);
        g.adi[b-1].push_back(a-1);
    }
 
    bool pos=false;
    for(int i=0; i<n; i++){
        if(g.dfs(i, -1, k, 0)){
            pos=true;
        }
    }
 
    if(pos){
        cout << "YES\n";
    }
    else{
        cout << "NO\n";
    }
    cout << 0 << "\n";
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 30