Submission #732922

#	Time	Username	Problem	Language	Result	Execution time	Memory
732922		Vanilla	Valley (BOI19_valley)	C++17	100 / 100	241 ms	59196 KiB

valley

#include <bits/stdc++.h>
#include <fstream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
struct custom_hash {static uint64_t splitmix64(uint64_t x) {x += 0x9e3779b97f4a7c15;x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;x = (x ^ (x >> 27)) * 0x94d049bb133111eb;return x ^ (x >> 31);}size_t operator()(uint64_t x) const {static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();return splitmix64(x + FIXED_RANDOM);}};
// string __fname = ""; ifstream in (__fname + ".in"); ofstream out (__fname + ".out"); 
// #define cin in 
// #define cout out
#define int64 long long
#define uint64 unsigned long long
#define x first
#define y second
#define pb push_back
#define pii pair <int, int> 
#define pii64 pair <int64, int64>
#define db(x) cout << "> " << #x << ": " << (x) << "\n"
#define qr queries()
#define yn(x) if (x) {ctn("Yes");}else {ctn("No");}
void solve(int);
void queries(){int n;cin >> n;for (int i = 1; i <= n; i++) solve(i);}
template<class T>T ceildiv(T a, T b) {return a / b + !!(a % b);}
template<class T>T gcd (T a, T b){return (b ? gcd(b, a % b): a);}
template<class T>T lcm (T a, T b){return a * b / gcd(a, b);}
// // // // // // // // // // // // // // // // // // // // // // 
/*                  TEMPLATE - VANILLA                         */
// // // // // // // // // // // // // // // // // // // // // //
const int ddx[] = {-1, -1, 0, 1, 1, 1, 0, -1};
const int ddy[] = {0, 1, 1, 1, 0, -1, -1, -1};
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
const double pi = 3.14159265359;
const double eps = 1e-6;
const int64 hash_inv = 940594066;
const int64 hash_p = 101;
const int64 mod = 1e9 + 7;
const int maxn = 1e5 + 2;
const int lg = 20;
vector <pii64> ad [maxn];
vector <pii> eg;
int lca [maxn][lg];
int64 dp [maxn][lg];
int64 dist [maxn][lg];
int depth [maxn];
int64 sub [maxn];
int is[maxn];
int n,s,q,r;

void solve(int id){
    
    return;
}

void dfs (int u, int p = -1) {
    if (is[u]) sub[u] = 0;
    for (auto [v, c]: ad[u]) {
        if (v == p) continue;
        depth[v] = depth[u] + 1;
        dfs(v, u);
        lca[v][0] = u;
        dist[v][0] = c;
        sub[u] = min(sub[u], sub[v] + c);
    }
}

int get (int u, int p) {
    for (int i = lg - 1; i >= 0; i--){
        if (p & (1 << i)) u = lca[u][i];
    }
    return u;
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout << fixed; cout << setprecision(10); 
    cin >> n >> s >> q >> r;
    for (int i = 1; i <= n; i++) sub[i] = 1e15;
    for (int i = 0; i < n - 1; i++){
        int u,v,c;
        cin >> u >> v >> c;
        ad[u].push_back({v, c});
        ad[v].push_back({u, c});
        eg.push_back({u, v});
    }
    for (int i = 0; i < s; i++){
        int x;
        cin >> x;
        is[x] = 1;
    }
    dfs(r);
    for (int i = 1; i <= n; i++){
        dp[i][0] = min(sub[i], sub[lca[i][0]] + dist[i][0]);
    }
    for (int k = 1; k < lg; k++){
        for (int i = 1; i <= n; i++){
            lca[i][k] = lca[lca[i][k-1]][k-1];
            dist[i][k] = dist[i][k-1] + dist[lca[i][k-1]][k-1];
            dp[i][k] = min(dp[i][k-1], dp[lca[i][k-1]][k-1] + dist[i][k-1]);
        }
    }
    // dfsr(r);
    while (q--) {
        int idx, nd;
        cin >> idx >> nd;
        idx--;
        auto [x,y] = eg[idx];
        if (depth[x] < depth[y]) swap(x, y);
        int diff = depth[nd] - depth[x];
        if (diff >= 0 && get(nd, diff) == x) {
            int64 rs = sub[nd], sf = 0;
            for (int i = lg - 1; i >= 0; i--){
                if (diff & (1 << i)) {
                    rs = min(rs, sf + dp[nd][i]);
                    sf+=dist[nd][i];
                    nd = lca[nd][i];
                }
            }
            if (rs >= 1e15) {
                cout << "oo\n";
            }
            else {
                cout << rs << "\n";
            }
        }
        else {
            cout << "escaped\n";
        }
    }
    return 0;
}

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