Submission #1136219

#TimeUsernameProblemLanguageResultExecution timeMemory
1136219SharkyFactories (JOI14_factories)C++20
100 / 100
4067 ms356712 KiB
#include <bits/stdc++.h>
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

#define int long long
#define fi first
#define se second

const int N = 5e5 + 5;
int sz[N], bl[N], mnd[N];
vector<pair<int, int>> adj[N], anc[N];
bool c[N];

void dfs_sz(int u, int p) {
    sz[u] = 1;
    for (auto& [v, w] : adj[u]) {
        if (v == p || c[v]) continue;
        dfs_sz(v, u);
        sz[u] += sz[v];
    }
}

int dfs_cent(int u, int p, int tot) {
    int res = -1, mx = 0;
    for (auto& [v, w] : adj[u]) {
        if (v == p || c[v]) continue;
        res = max(res, dfs_cent(v, u, tot));
        mx = max(mx, sz[v]);
    }
    mx = max(mx, tot - sz[u]);
    if (mx <= tot / 2) res = max(res, u);
    return res;
}

void redfs(int cent, int u, int p, int dist) {
    anc[u].push_back({cent, dist});
    for (auto& [v, w] : adj[u]) {
        if (v == p || c[v]) continue;
        redfs(cent, v, u, dist + w);
    }
}

void decomp(int u) {
    dfs_sz(u, -1);
    int cent = dfs_cent(u, -1, sz[u]);
    c[cent] = 1;
    redfs(cent, cent, -1, 0);
    for (auto& [v, w] : adj[cent]) {
        if (c[v]) continue;
        decomp(v);
    }
}

const int inf = 1e18;
#define Int int32_t

void Init(Int n, Int a[], Int b[], Int d[]) {
    for (int i = 0; i < n - 1; i++) {
        a[i]++, b[i]++;
        adj[a[i]].push_back({b[i], d[i]});
        adj[b[i]].push_back({a[i], d[i]});
    }
    decomp(1);
    for (int i = 1; i <= n; i++) mnd[i] = inf;
}

int Query(Int s, Int x[], Int t, Int y[]) {
    for (int i = 0; i < s; i++) {
        x[i]++;
        for (auto& [u, dist] : anc[x[i]]) mnd[u] = min(mnd[u], dist);
    }
    int ans = inf;
    for (int i = 0; i < t; i++) {
        y[i]++;
        for (auto& [u, dist] : anc[y[i]]) ans = min(ans, mnd[u] + dist);
    }
    for (int i = 0; i < s; i++) {
        for (auto& [u, dist] : anc[x[i]]) mnd[u] = inf;
    }
    return ans;
}
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