Submission #2966076

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Source Code Expand

#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<iomanip>
#include<math.h>
#include<complex>
#include<queue>
#include<deque>
#include<map>
#include<set>
#include<bitset>
using namespace std;
#define REP(i,m,n) for(int i=(int)m ; i < (int) n ; ++i )
#define rep(i,n) REP(i,0,n)
typedef long long ll;
typedef pair<int,int> pint;
typedef pair<ll,int> pli;
const int inf=1e9+7;
const ll longinf=1LL<<60 ;
const ll mod=1e9+7 ;
int dx[4]={1,0,-1,0} , dy[4]={0,1,0,-1} ;
struct LCA{
	int n,h;
	vector<vector<int>> v,par;
	vector<int> depth,ord;
	LCA(int sz):n(sz),v(n),depth(n),ord(n){
		h=1;
		while((1<<h)<n)h++;
		par.assign(h,vector<int>(n,-1));
	}

	void add_edge(int x,int y){
		v[x].push_back(y);
		v[y].push_back(x);
	}	

	void dfs(int x,int p,int d,int& i){
		par[0][x]=p;
		depth[x]=d;
		for(auto to:v[x])if(to!=p)dfs(to,x,d+1,i);
		ord[x]=i++;
	}
	
	void build(){
		int k=0;
		dfs(0,-1,0,k);
		rep(i,h-1){
			rep(j,n){
				if(par[i][j]<0)par[i+1][j]=-1;
				else par[i+1][j]=par[i][par[i][j]];
			}
		}
	}
	
	int lca(int u,int v){
		if(depth[u]>depth[v])swap(u,v);
		rep(i,h)if((depth[v]-depth[u])>>i &1)v=par[i][v];
		if(u==v)return u;
		for(int i=h-1;i>=0;i--){
			if(par[i][u]!=par[i][v]){
				u=par[i][u];
				v=par[i][v];
			}
		}
		return par[0][u];
	}
	
	int dist(int u,int v){
		return depth[u]+depth[v]-2*depth[lca(u,v)];
	}
};
 
int main(){
    int n;
	cin>>n;
	LCA lca(n);
    rep(i,n-1){
        int x,y;
        cin>>x>>y;
		lca.add_edge(x-1, y-1);
    }
    lca.build();
    int q;
    cin>>q;
    rep(aaa,q){
      int m,k;scanf("%d%d",&m,&k);
      vector<pint> w;
      rep(i,m){
        int r;scanf("%d",&r);
		r--;
        w.push_back({lca.ord[r],r});
        }
      sort(w.begin(),w.end());
      int ans=-1;
      rep(i,m-k+1){
        int ret=lca.lca(w[i].second,w[i+k-1].second);
        ans=max(ans,lca.depth[ret]);
        }
      printf("%d\n",ans);
      }
  
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:87:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
       int m,k;scanf("%d%d",&m,&k);
                                  ^
./Main.cpp:90:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         int r;scanf("%d",&r);
                             ^

Judge Result