Submission #917159

#	Time	Username	Problem	Language	Result	Execution time	Memory
917159		dilanyan	Evacuation plan (IZhO18_plan)	C++17	100 / 100	461 ms	50376 KiB

plan

//-------------dilanyan------------\\ 
 
#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#include<stdio.h>
using namespace std;
 
//------------------KarginDefines--------------------\\ 
 
#define ll long long
#define pb push_back
#define all(u) (u).begin(), (u).end()
#define pqueue priority_queue
#define upper upper_bound
#define lower lower_bound
#define umap unordered_map
#define uset unordered_set
#define Kargin ios_base::sync_with_stdio(false);cin.tie(NULL);
#define Usaco freopen(".in", "r", stdin); freopen(".out", "w", stdout);
 
 
//-------------------KarginConstants------------------\\ 
 
const ll mod = 1000000007;
const ll inf = 1e9 + 15;
 
//-------------------KarginCode------------------------\\ 
 
const int N = 100005;

int n;

vector<pair<int, int>> g[N];
int dist[N];
bool vis[N];

bool cmp(int u,int v) {
    return dist[u] > dist[v];
}

int p[N], s[N];
vector<int> t[N];

void setdsu() {
    for (int i = 1;i <= n;i++) p[i] = i, s[i] = 1;
}

int get(int u) {
    return p[u] = (u == p[u] ? u : get(p[u]));
}

bool merge(int u, int v) {
    int pu = get(u), pv = get(v);
    if (pu == pv) return false;
    if (s[pu] < s[pv]) swap(u, v), swap(pu, pv);
    s[pu] += s[pv];
    p[pv] = pu;
    t[u].pb(v), t[v].pb(u);
    return (s[pu] == n);
}

int tin[N], tout[N], tim = 0;
int up[N][20], mn[N][20], d[N];

void dfs(int u, int p) {
    tin[u] = tim++;
    for (int v : t[u]) {
        if (p == v) continue;
        up[v][0] = u;
        mn[v][0] = min(dist[u], dist[v]);
        d[v] = d[u] + 1;
        dfs(v, u);
    }
    tout[u] = tim;
}

bool anc(int u, int v) {
    return (tin[u] <= tin[v] && tout[u] >= tout[v]);
}

int lca(int u, int v) {
    if (anc(u, v)) return u;
    if (anc(v, u)) return v;
    for (int i = 19;i >= 0;i--) {
        if (!anc(up[u][i], v)) u = up[u][i];
    }
    return up[u][0];
}

void KarginSolve() {
    int m;
    cin >> n >> m;
    for (int i = 0;i < m;i++) {
        int u, v, w;
        cin >> u >> v >> w;
        g[u].pb({ v,w }), g[v].pb({ u,w });
    }
    int k; cin >> k;
    fill(dist + 1, dist + n + 1, inf);
    pqueue<pair<int, int>> pq;
    for (int i = 0; i < k;i++) {
        int u; cin >> u;
        pq.push({ 0,u }), dist[u] = 0;
    }
    while (!pq.empty()) {
        int u = pq.top().second; pq.pop();
        if (vis[u]) continue;
        vis[u] = true;
        for (auto it : g[u]) {
            int v = it.first, w = it.second;
            if (dist[v] > dist[u] + w) {
                dist[v] = dist[u] + w;
                pq.push({ -dist[v],v });
            }
        }
    }
    vector<int> a;
    for (int i = 1;i <= n;i++) a.pb(i);
    sort(all(a), cmp);
    setdsu();
    for (int u : a) {
        for (auto it : g[u]) {
            int v = it.first;
            if(dist[u] > dist[v]) continue;
            if (merge(u, v)) break;
        }
    }
    // for (int i = 1;i <= n;i++) {
    //     cout << i << " : " << dist[i] << "-> ";
    //     for (int v : t[i]) cout << v << ' ';
    //     cout << '\n';

    // }
    dfs(1, 0);
    up[1][0] = 1, mn[1][0] = dist[1];
    for (int j = 1;j < 20;j++) {
        for (int i = 1;i <= n;i++) {
            up[i][j] = up[up[i][j - 1]][j - 1];
            mn[i][j] = min(mn[i][j - 1], mn[up[i][j - 1]][j - 1]);
        }
    }
    int q; cin >> q;
    while (q--) {
        int u, v;
        cin >>  u>> v;
        int l = lca(u, v);
        int ans = inf;
        int du = d[u] - d[l], dv = d[v] - d[l];
        for (int i = 0;i < 20;i++) {
            if (du & (1 << i)) ans = min(ans, mn[u][i]), u = up[u][i];
            if (dv & (1 << i)) ans = min(ans, mn[v][i]), v = up[v][i];
        }
        cout << ans << '\n';
    }
}
 
int main() {
    //Usaco
    Kargin;
    int test = 1;
    //cin >> test;
    while (test--) {
        KarginSolve();
    }
    return 0;
}

Compilation message (stderr)

plan.cpp:1:1: warning: multi-line comment [-Wcomment]
    1 | //-------------dilanyan------------\\
      | ^
plan.cpp:8:1: warning: multi-line comment [-Wcomment]
    8 | //------------------KarginDefines--------------------\\
      | ^
plan.cpp:22:1: warning: multi-line comment [-Wcomment]
   22 | //-------------------KarginConstants------------------\\
      | ^
plan.cpp:27:1: warning: multi-line comment [-Wcomment]
   27 | //-------------------KarginCode------------------------\\
      | ^

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46