Submission #874459

#	Time	Username	Problem	Language	Result	Execution time	Memory
874459		winter0101	Jail (JOI22_jail)	C++14	61 / 100	5022 ms	33112 KiB

jail

#include<bits/stdc++.h>
using namespace std;
#define all(fl) fl.begin(),fl.end()
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define lb lower_bound
#define ub upper_bound
#define sz(a) (int)a.size()
#define pii pair<int,int>
#define pli pair<long long,int>
#define gcd __gcd
#define lcm(x,y) x*y/__gcd(x,y)
#define lastbit(i) __builtin_ctz(i)
const int maxn=1e5+2e4+9;
vector<int>a[maxn];
pii b[maxn];
int st[maxn][19];
int d[maxn];
void dfs(int u,int par){
for (auto v:a[u]){
if (v==par)continue;
st[v][0]=u;
for1(i,1,17)st[v][i]=st[st[v][i-1]][i-1];
d[v]=d[u]+1;
dfs(v,u);
}
}
int lca(int u,int v){
if (d[u]<d[v])swap(u,v);
int k=d[u]-d[v];
for1(i,0,17)if (k>>i&1)u=st[u][i];
if (u==v)return u;
for2(i,17,0){
if (!st[u][i]||!st[v][i])continue;
if (st[u][i]!=st[v][i]){
    u=st[u][i];
    v=st[v][i];
}
}
return st[u][0];
}
bool onpath(int u,int v,int k){
int t=lca(u,v);
if (lca(t,k)==t&&lca(k,u)==k)return 1;
if (lca(t,k)==t&&lca(k,v)==k)return 1;
return 0;
}
vector<int>g[maxn];
int scc=0;
int low[maxn],num[maxn],tme=0;
stack<int>t;
void redfs(int u){
t.push(u);
low[u]=num[u]=++tme;
for (auto v:g[u]){
if (num[v]==-1)continue;
if (num[v])low[u]=min(low[u],low[v]);
else {
    redfs(v);
    low[u]=min(low[u],low[v]);
}
}
if (low[u]==num[u]){
    scc++;
    while (!t.empty()&&t.top()!=u){
    num[t.top()]=-1;
    t.pop();
    }
    num[u]=-1;
    t.pop();
}
}
void solve(){
    int n;
    cin>>n;
    for1(i,1,n){
    a[i].clear();
    g[i].clear();
    }
    for1(i,1,n-1){
    int u,v;
    cin>>u>>v;
    a[u].pb(v);
    a[v].pb(u);
    }
    for1(i,0,17)for1(j,1,n)st[j][i]=0;
    dfs(1,0);
    int m;
    cin>>m;
    for1(i,1,m){
    low[i]=num[i]=0;
    cin>>b[i].fi>>b[i].se;
    }
    for1(i,1,m){
    for1(j,1,m){
    if (i==j)continue;
    if (onpath(b[i].fi,b[i].se,b[j].fi)){
    g[j].pb(i);
    //cout<<j<<" "<<i<<'\n';
    }
    if (onpath(b[i].fi,b[i].se,b[j].se)){
    g[i].pb(j);
    //cout<<i<<" "<<j<<'\n';
    }
    }
    }
    scc=tme=0;
    for1(i,1,m)if (!num[i])redfs(i);
    //cout<<low[1]<<" "<<num[1]<<" "<<low[2]<<" "<<num[2];
    if (scc==m)cout<<"Yes"<<'\n';
    else cout<<"No"<<'\n';
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    //freopen("temp.INP","r",stdin);
    //freopen("temp.OUT","w",stdout);
    int test;
    cin>>test;
    while (test--)solve();
}

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