Submission #893839

#	Time	Username	Problem	Language	Result	Execution time	Memory
893839		kigash	Valley (BOI19_valley)	C++17	100 / 100	179 ms	66900 KiB

valley

#include "bits/stdc++.h"
using namespace std;       

// #pragma comment(linker, "/stack:200000000")
// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")

using ll = long long;
using ld = long double;
#define pb push_back
#define ff first
#define ss second
#define sz(x) (ll)(x).size()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

void freopen(string s) { freopen((s+".in").c_str(), "r", stdin); freopen((s+".out").c_str(), "w", stdout); }
void IOIGold2024_InshAllah() { ios_base::sync_with_stdio(false); cin.tie(NULL); }
ll binmul(ll a, ll b, ll c) { ll res = 0; while(b) { if(b&1) (res += a) %= c; (a += a) %= c; b >>= 1; } return res; }
ll binpow(ll a, ll b, ll c) { ll res = 1; while(b) { if(b&1) (res *= a) %= c; (a *= a) %= c; b >>= 1; } return res; }
template<typename T> T gcd(T a, T b) { if(b==0) return a; return gcd(b, a%b); }
template<typename T> T lcm(T a, T b) { return a/gcd(a, b)*b; }
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ld rnd() { return rng()%INT_MAX*1.0/INT_MAX; }

const ll inf = 1e18+7, MX = LLONG_MAX, MN = LLONG_MIN;
const ll mod = 1e9+7, N = 3e5+5;
vector<pair<ll, ll>> g[N];
ll d[N], dist[N], dp[N], up[N][20], t[N][20], tin[N], tout[N], timer;
pair<ll, ll> edge[N];

void dfs(ll v, ll p) {
    tin[v] = ++timer;
    up[v][0] = p, dist[v] = dist[p]+1;
    for(ll i=1; i<20; i++) up[v][i] = up[up[v][i-1]][i-1];
    for(auto [to, w]: g[v]) {
        if(to==p) continue;
        d[to] = d[v]+w;
        dfs(to, v);
        dp[v] = min(dp[v], dp[to]+w);
    }
    tout[v] = ++timer;
}

void qfs(ll v, ll p) {
    t[v][0] = dp[v]-d[v];
    for(ll i=1; i<20; i++) t[v][i] = min(t[v][i-1], t[up[v][i-1]][i-1]);
    for(auto [to, w]: g[v]) {
        if(to==p) continue;
        qfs(to, v);
    }
}

void kigash() {
    ll n, m, q, x;
    cin>>n>>m>>q>>x;
    for(ll i=1; i<n; i++) {
        ll u, v, w;
        cin>>u>>v>>w;
        edge[i] = {u, v};
        g[u].pb({v, w}), g[v].pb({u, w});
    }
    for(ll i=1; i<=n; i++) dp[i] = inf;
    for(ll i=1; i<=m; i++) {
        ll v;
        cin>>v;
        dp[v] = 0;
    }
    dfs(x, 0), qfs(x, 0);
    while(q--) {
        ll a, b;
        cin>>a>>b;
        ll u = edge[a].ff, v = edge[a].ss;
        if(dist[u]>dist[v]) swap(u, v);
        if(tin[v]<=tin[b] && tout[b]<=tout[v]) {
            ll k = dist[b]-dist[v], b_ = b, mn = inf;
            for(ll i=19; i>=0; i--) {
                if(k&(1<<i)) {
                    mn = min(mn, t[b][i]);
                    b = up[b][i];
                }
            }
            mn = min(mn, t[v][0]);
            if(mn+d[b_]>=inf) cout<<"oo\n";
            else cout<<mn+d[b_]<<"\n";
        }
        else cout<<"escaped\n";
    }
    return;
}

signed main(/*Kigash Amir*/) {
    // freopen("");
    IOIGold2024_InshAllah();
    ll tt = 1;
    // cin>>tt;
    for(ll i=1; i<=tt; i++) {
        kigash();
    }
}

Compilation message (stderr)

valley.cpp: In function 'void freopen(std::string)':
valley.cpp:17:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 | void freopen(string s) { freopen((s+".in").c_str(), "r", stdin); freopen((s+".out").c_str(), "w", stdout); }
      |                          ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:17:73: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 | void freopen(string s) { freopen((s+".in").c_str(), "r", stdin); freopen((s+".out").c_str(), "w", stdout); }
      |                                                                  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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