Submission #875634

#	Time	Username	Problem	Language	Result	Execution time	Memory
875634		dimashhh	Jail (JOI22_jail)	C++17	0 / 100	1 ms	604 KiB

jail

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e3 + 10, MOD = 998244353;

vector<int> g[N];
int timer = 0,tin[N],tout[N],n,m,s[N],t[N],blocked[N],c[N],pp[N];
void dfs(int v,int pr = 0){
    tin[v] = ++timer;
    pp[v] = pr;
    for(int to:g[v]){
        if(to == pr) continue;
        dfs(to,v);
    }
    tout[v] = ++timer;
}
bool is(int v,int u){
    return (tin[v] <= tin[u] && tout[v] >= tout[u]);
}
bool can(int i){
    int v =s[i],u = t[i];
    while(!is(v,u)){
        if(c[v] && c[v] != i) return false;
        v = pp[v];
    }
    if(!is(u,v)){
        if(c[u] && c[u] != i) return false;
        u = pp[u];
    }
    assert(v == u);
    if((c[v] && c[v] != i) || (c[u] && c[u] != i)) return false;
    return 1;
}
void test(){
    timer =0 ;
    cin >> n;
    for(int i = 1;i <= n;i++)
        g[i].clear();
    for(int i = 1;i <= n - 1;i++){
        int x,y;
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
        c[x] = c[y] = 0;
    }
    dfs(1);
    cin >> m;
    for(int i = 1;i <= m;i++){
        blocked[i] = 0;
    }
    for(int i = 1;i <= m;++i){
        cin >> s[i] >> t[i];
        c[s[i]] = i;
    }
    // cout << can(2);
    for(int i = 1;i <= m;i++){
        bool ok = false;
        for(int j = 1;j <= m;j++){
            // cout << .
            // cout << j << ' ' << can(j) << '\n';
            if(blocked[j] || !can(j)) continue;
            blocked[j] = 1;
            c[s[j]] = 0;
            c[t[j]]  =j;
            ok = 1;
            break;
        }
        // cout << can(1) << '\n';
        if(!ok){
            cout << "No\n";
            return;
        }
    }
    cout << "Yes\n";
}
main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int T = 1;
    cin >> T;
    for (int i = 1; i <= T; i++)
    {
        test();
    }
}

Compilation message (stderr)

jail.cpp:76:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   76 | main()
      | ^~~~

• 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