Submission #495202

#	Time	Username	Problem	Language	Result	Execution time	Memory
495202		xynex	Evacuation plan (IZhO18_plan)	C++17	100 / 100	798 ms	86344 KiB

plan

/*
* Author: xynex
* Created: 18.12.2021 10:42
* Why am I so stupid? :c
* Slishkom slab
*/

#include <bits/stdc++.h>

// #pragma GCC optimize("inline")
// #pragma GCC optimize("-fgcse,-fgcse-lm")
// #pragma GCC optimize("-ftree-pre,-ftree-vrp")
// #pragma GCC optimize("-ffast-math")
// #pragma GCC optimize("-fipa-sra")
// #pragma GCC optimize("-fpeephole2")
// #pragma GCC optimize("-fsched-spec")
// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
// #pragma GCC optimize("unroll-loops")

using namespace std;

#define ll long long
#define dl double long
#define ull unsigned long long
#define pr pair
#define vt vector
#define ff first
#define ss second
#define mp make_pair
#define sz(a) (int)a.size()
#define pb push_back
#define pf push_front
#define popB pop_back
#define popF pop_front
#define bit_count __builtin_popcount
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sp(x) fixed << setprecision(x)

template<typename T> T get_rand(T l, T r) {
    random_device rd;
    mt19937 gen(rd());
    return uniform_int_distribution<T>(l, r)(gen);
}

template<typename T> T lcm(T a, T b) { return a * (b / __gcd(a, b)); }

template<class A> void read(vt<A>& v);
template<class A, size_t S> void read(array<A, S>& a);
template<class T> void read(T& x) { cin >> x; }
void read(double& d) { string t; read(t); d = stod(t); }
void read(long double& d) { string t; read(t); d = stold(t); }
template<class H, class... T> void read(H& h, T&... t) { read(h); read(t...); }
template<class A> void read(vt<A>& x) { for (auto& a : x) read(a); }
template<class A, size_t S> void read(array<A, S>& x) { for (auto& a : x) read(a); }

string to_string(char c) { return string(1, c); }
string to_string(bool b) { return b ? "true" : "false"; }
string to_string(const char* s) { return string(s); }
string to_string(string s) { return s; }
string to_string(vt<bool> v) { string res; for (int i = 0; i < sz(v); ++i) res += char('0' + v[i]); return res; }
template<size_t S> string to_string(bitset<S> b) { string res; for (int i = 0; i < S; ++i) res += char('0' + b[i]); return res; }
template<class T> string to_string(T v) { bool f = 1; string res; for (auto x : v) { if (!f) res += ' '; f = 0; res += to_string(x); } return res; }

template<class A> void write(A x) { cout << to_string(x); }
template<class H, class... T> void write(const H& h, const T&... t) { write(h); write(t...); }

void print() { write("\n"); }
template<class H, class... T> void print(const H& h, const T&... t) { write(h); if (sizeof...(t)) write(' '); print(t...); }

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

const int MOD = 1e9 + 7;
const int N = 5e5 + 5;
const ll INF = 9e18;
const int M = 3e3 + 5;
const dl pi = acos(-1);
const dl eps = 1e-12;
const int sq = 700;

int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};
/* ll vs int*/

void precalc() {

}

class dsu {
  public:
    vector<int> p;
    int n;
    dsu(int _n) : n(_n) {
        p.resize(n);
        iota(p.begin(), p.end(), 0);
    }
    inline int get(int x) { return (x == p[x] ? x : (p[x] = get(p[x]))); }
    inline bool unite(int x, int y) {
        x = get(x);
        y = get(y);
        if (x != y) {
            p[x] = y;
            return true;
        }
        return false;
    }
};


int dist[N];
vt<pr<int, int> > g[N];
int n, k, m;
int npp[N];
void dijkstra() {
    set<pr<int, int> > q;
    for(int i = 1; i <= n; ++i) dist[i] = MOD;
    for(int i = 1; i <= k; ++i) {
        q.insert({0, npp[i]});
        dist[npp[i]] = 0;
    }
    while(!q.empty()) {
        int v = (*q.begin()).ss;
        q.erase(q.begin());
        for(auto to : g[v]) {
            if(dist[to.ff] > dist[v] + to.ss) {
                q.erase(mp(dist[to.ff], to.ff));
                dist[to.ff] = dist[v] + to.ss;
                q.insert(mp(dist[to.ff], to.ff));
            }
        }
    }
}
int l[N], r[N];
int dp[30][N], mx[30][N];
dsu p(N);
int dep[N];
vt<pr<int, int> > graph[N];
void dfs_lca(int v, int par, int lev) {
    dp[0][v] = par;
    dep[v] = lev;
    for(auto to : graph[v]) {
        if(to.ff == par) continue;
        mx[0][to.ff] = to.ss;
        dfs_lca(to.ff, v, lev + 1);
    }
}
void find_ancestor() {
    for(int i = 1; i < 30; ++i) {
        for(int j = 1; j <= n; ++j) {
            dp[i][j] = dp[i - 1][dp[i - 1][j]];
            mx[i][j] = min(mx[i - 1][j], mx[i - 1][dp[i - 1][j]]);
        }
    }
}
int getMax(int a, int b) {
    if(dep[b] < dep[a]) swap(a, b);
    int ans = MOD;
    int diff = dep[b] - dep[a];
    while(diff > 0) {
        int log = log2(diff);
        ans = min(ans, mx[log][b]);
        b = dp[log][b];
        diff -= (1 << log);
    }
    while(a != b) {
        int i = log2(dep[a]);
        while(i > 0 && dp[i][a] == dp[i][b])i--;
        ans = min(ans, mx[i][a]);
        ans = min(ans, mx[i][b]);
        a = dp[i][a];
        b = dp[i][b];
    }
    return ans;
}
void solve() {
    read(n, m);
    for(int i = 1; i <= m; ++i) {
        int w; read(l[i], r[i], w);
        g[l[i]].pb({r[i], w});
        g[r[i]].pb({l[i], w});
    }
    read(k);
    for(int i = 1; i <= k; ++i) {
        read(npp[i]);
    }
    dijkstra();
    vt<pr<int, pr<int, int> > > g1;
    for(int i = 1; i <= m; ++i) {
        int w = min(dist[l[i]], dist[r[i]]);
        g1.pb({-w, {l[i], r[i]}});
        g1.pb({-w, {r[i], l[i]}});
    }
    sort(all(g1));
    for(auto cur : g1) {
        int v = cur.ss.ff, to = cur.ss.ss, w = cur.ff;
        if(p.get(v) != p.get(to)) {
            graph[v].pb({to, -w});
            graph[to].pb({v, -w});
            p.unite(v, to);
        }
    }
    dfs_lca(1, 0, 0);
    find_ancestor();
    int q; read(q);
    while(q--) {
        int x, y; read(x, y);
        print(getMax(x, y));
    }
}

int main() {
    //freop("");
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    //read(t);
    precalc();
    for (int i = 1; i <= t; ++i) {
        //write("Case #" + to_string(i) + ": ");
        solve();
    }
    return 0;
}

Compilation message (stderr)

plan.cpp: In function 'void freop(std::string)':
plan.cpp:73:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:74:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |     freopen((s + ".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