Submission #468308

#	Time	Username	Problem	Language	Result	Execution time	Memory
468308		Killer2501	Valley (BOI19_valley)	C++14	100 / 100	255 ms	56096 KiB

valley

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define task "tests"
#define pll pair<ll, ll>
#define pi pair<ll, pll>
#define fi first
#define se second

using namespace std;
const ll mod = 1e15+7;
const ll N = 2e5+5;
const int base = 313;
ll n, m, t, k, T, ans, tong, c[N], a[N], b[N], h[N], mn[N][20], cnt, P[N][20], e, in[N], out[N], dep[N];
vector<pll> adj[N];
ll pw(ll k, ll n)
{
    ll total = 1;
    for(; n; n >>= 1)
    {
        if(n & 1)total = total * k % mod;
        k = k * k % mod;
    }
    return total;
}
void dfs(ll u, ll p)
{
    in[u] = ++cnt;
    for(pll v: adj[u])
    {
        if(v.se == p)continue;
        dep[v.se] = dep[u] + v.fi;
        h[v.se] = h[u] + 1;
        P[v.se][0] = u;
        dfs(v.se, u);
        a[u] = min(a[u], a[v.se]+v.fi);
        
    }
    out[u] = cnt;
}
void cal(ll u, ll p)
{
    for(int i = 1; (1<<i) <= h[u]; i ++)
    {
        P[u][i] = P[P[u][i-1]][i-1];
        mn[u][i] = min(mn[u][i-1], mn[P[u][i-1]][i-1]);
    }
    for(pll v : adj[u])
    {
        if(v.se == p)continue;
        mn[v.se][0] = a[u] - dep[u];
        cal(v.se, u);
    }
}
ll getans(ll u, ll dis)
{
    ll total = a[u] - dep[u];
    for(int i = 18; i >= 0; i --)
    {
        if((dis >> i) & 1)
        {
            total = min(total, mn[u][i]);
            u = P[u][i];
        }
    }
    return total;
}
void sol()
{
    cin >> n >> k >> m >> e;
    fill_n(a, n+1, mod);
    for(int i = 1; i < n; i ++)
    {
        ll x, y, w;
        cin >> x >> y >> w;
        adj[x].pb({w, y});
        adj[y].pb({w, x});
        b[i] = x;
        c[i] = y;
    }
    for(int i = 1; i <= k; i ++)
    {
        cin >> t;
        a[t] = 0;
    }
    dfs(e, 0);
    cal(e, 0);
    while(m -- > 0)
    {
        ll x, y;
        cin >> x >> y;
        //cout << b[x] <<" "<<c[x]<<" "<<x <<'\n';
        if(h[c[x]] < h[b[x]])x = b[x];
        else x = c[x];
        //cout << x <<" "<<y<<'\n';
        if(in[x] <= in[y] && out[y] <= out[x])
        {
            ans = getans(y, h[y]-h[x]);
            if(ans+dep[y] < mod)cout << ans+dep[y] << '\n';
            else cout <<"oo"<<'\n';
        }
        else cout << "escaped" << '\n';
    }
}
int main()
{
    if(fopen(task".in", "r"))
    {
       freopen(task".in", "r", stdin);
       freopen(task".out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int ntest = 1;
    //cin >> ntest;
    while(ntest -- > 0)
    sol();
}
/*
5 1
0 1 2
0 2 3
1 3 5
2 4 6
1 1
4 3
*/

Compilation message (stderr)

valley.cpp: In function 'int main()':
valley.cpp:109:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  109 |        freopen(task".in", "r", stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:110:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |        freopen(task".out", "w", stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 23 / 23
• Subtask 4: 41 / 41