Submission #890935

#	Time	Username	Problem	Language	Result	Execution time	Memory
890935		vjudge1	Jail (JOI22_jail)	C++17	0 / 100	0 ms	348 KiB

jail

#include <bits/stdc++.h>
#define int long long
#define all(x) x.begin(),x.end()
#define ff first
#define ss second
#define pb push_back
using namespace std;
const int N=1000;
vector <int> g[N];
int d[N],p[N];
int jmp[20][N];
void dfs(int v,int par){
    p[v]=par;
    for(auto to : g[v]){
        if(to!=par){
            d[to]=d[v]+1;
            dfs(to,v);
        }
    }
}
int lca(int a,int b){
    if(d[a]<d[b]){
        swap(a,b);
    }
    int curv=a,curu=b;
    for(int j=19;j>=0;j--){
        if(d[jmp[curv][j]]>=d[curu]){
            curv=jmp[curv][j];
        }
    }
    if(curv==curu){
        return curv;
    }
    for(int j=19;j>=0;j--){
        if(jmp[curv][j]!=jmp[curu][j]){
            curv=jmp[curv][j];
            curu=jmp[curu][j];
        }
    }
    return p[curv];
}
signed main(){
    ios_base::sync_with_stdio();
    cin.tie(0);
    int t;cin>>t;
    while(t--){
        
        
        int n;cin>>n;
        for(int i=0;i<n-1;i++){
            int u,v;cin>>u>>v;
            g[u].pb(v);
            g[v].pb(u);
        }
        
        dfs(1,0);
        p[1]=1;
        for(int i=1;i<=n;i++){
            jmp[i][0]=p[i];
        }
        for(int j=1;j<20;j++){
            for(int i=1;i<=n;i++){
                jmp[i][j]=jmp[jmp[i][j-1]][j-1];
            }
        }
        
        int m;cin>>m;
        vector <int> s(m),t(m);
        vector <vector <int> > path(m);
        for(int i=0;i<m;i++)cin>>s[i]>>t[i];
        for(int i=0;i<m;i++){
            int x=lca(s[i],t[i]);
            int curv=s[i];
            path[i].pb(curv);
            while(curv!=x){
                curv=p[curv];
                path[i].pb(curv);
            }
            path[i].pop_back();
            vector <int> v;
            curv=t[i];
            v.pb(curv);
            while(curv!=x){
                curv=p[curv];
               v.pb(curv);
            }
            reverse(all(v));
            for(auto x : v)path[i].pb(x);
        }
        bool flag=true;
        for(int i=0;i<n;i++){
            set <int> st;
            int cnt=0;
            for(int j=0;j<m;j++){
                if(path[j].size()>=i+1){
                    cnt++;
                    st.insert(path[j][i]);
                }
                
            }
            if(st.size()!=cnt){
                flag=false;break;
            }
        }
        if(flag)cout<<"Yes\n";
        else cout<<"No\n";
        
        
        for(int i=1;i<=n;i++){
            g[i].clear();
            d[i]=0;p[i]=0;
            for(int j=0;j<20;j++){
                jmp[i][j]=0;
            }
        }
    }
}

Compilation message (stderr)

jail.cpp: In function 'int main()':
jail.cpp:95:34: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   95 |                 if(path[j].size()>=i+1){
      |                    ~~~~~~~~~~~~~~^~~~~
jail.cpp:101:25: warning: comparison of integer expressions of different signedness: 'std::set<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
  101 |             if(st.size()!=cnt){
      |                ~~~~~~~~~^~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 16
• Subtask 4: 0 / 28
• Subtask 5: 0 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23