Submission #553698

#	Time	Username	Problem	Language	Result	Execution time	Memory
553698		SmolBrain	Evacuation plan (IZhO18_plan)	C++17	100 / 100	810 ms	104072 KiB

plan

// Om Namah Shivaya
// GM in 98 days

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define pb push_back
#define conts continue
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}
template<typename T> void amin(T &a, T b) { a = min(a, b); }
template<typename T> void amax(T &a, T b) { a = max(a, b); }

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;
const int LOG = 17;

vector<pll> adj[maxn], adj2[maxn];
vector<ll> dis(maxn, inf2), depth(maxn);
vector<bool> vis(maxn);
vector<vector<ll>> up(maxn, vector<ll>(LOG)), mnw(maxn, vector<ll>(LOG, inf2));

struct DSU {
    // DSU data structure with 1-based indexing
    vector<int> par, rankk;

    DSU() {

    }

    DSU(int n) {
        init(n);
    }

    void init(int n) {
        par = vector<int>(n + 1);
        rankk = vector<int>(n + 1);
        rep(i, n + 1) create(i);
    }

    void create(int u) {
        par[u] = u;
        rankk[u] = 0;
    }

    int find(int u) {
        if (u == par[u]) return u;
        else return par[u] = find(par[u]);
    }

    bool same(int u, int v) {
        return find(u) == find(v);
    }

    void merge(int u, int v) {
        u = find(u), v = find(v);
        if (u == v) return;

        if (rankk[u] == rankk[v]) rankk[u]++;
        if (rankk[u] < rankk[v]) swap(u, v);

        par[v] = u;
    }
};

void dfs(ll node, ll par) {
    for (auto [child, w] : adj2[node]) {
        if (child == par) conts;

        up[child][0] = node;
        mnw[child][0] = w;

        rep1(j, LOG - 1) {
            up[child][j] = up[up[child][j - 1]][j - 1];
            mnw[child][j] = min(mnw[child][j - 1], mnw[up[child][j - 1]][j - 1]);
        }

        depth[child] = depth[node] + 1;

        dfs(child, node);
    }
}

pll lift(ll node, ll k) {
    ll mn = inf2;

    rep(j, LOG) {
        if (k & (1 << j)) {
            amin(mn, mnw[node][j]);
            node = up[node][j];
        }
    }

    return {node, mn};
}

ll get(ll u, ll v) {
    if (depth[u] < depth[v]) swap(u, v);
    ll k = depth[u] - depth[v];
    auto res = lift(u, k);

    ll mn = inf2;
    u = res.ff, mn = res.ss;

    if (u == v) return mn;

    rev(j, LOG - 1, 0) {
        if (up[u][j] != up[v][j]) {
            amin(mn, mnw[u][j]);
            amin(mn, mnw[v][j]);

            u = up[u][j];
            v = up[v][j];
        }
    }

    amin(mn, mnw[u][0]);
    amin(mn, mnw[v][0]);

    return mn;
}

void solve(int test_case)
{
    ll n, m; cin >> n >> m;
    rep1(i, m) {
        ll u, v, w; cin >> u >> v >> w;
        adj[u].pb({v, w}), adj[v].pb({u, w});
    }

    priority_queue< pll, vector<pll>, greater<pll> > pq;

    ll k; cin >> k;
    rep1(i, k) {
        ll u; cin >> u;
        pq.push({0, u});
        dis[u] = 0;
    }

    while (!pq.empty()) {
        auto [cost, node] = pq.top();
        pq.pop();

        if (vis[node]) conts;
        vis[node] = 1;

        for (auto [child, w] : adj[node]) {
            ll cost2 = cost + w;
            if (cost2 < dis[child]) {
                dis[child] = cost2;
                pq.push({cost2, child});
            }
        }
    }

    vector<array<ll, 3>> edges;
    rep1(node, n) {
        for (auto [child, w] : adj[node]) {
            ll cost = min(dis[node], dis[child]);
            edges.pb({cost, node, child});
        }
    }

    sort(rall(edges));
    DSU dsu(n);

    for (auto [w, u, v] : edges) {
        if (dsu.same(u, v)) conts;
        dsu.merge(u, v);
        adj2[u].pb({v, w}), adj2[v].pb({u, w});
    }

    dfs(1, -1);

    ll q; cin >> q;

    while (q--) {
        ll u, v; cin >> u >> v;
        ll ans = get(u, v);
        cout << ans << endl;
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;
    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message (stderr)

plan.cpp: In function 'void usaco(std::string)':
plan.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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