Submission #467810

#	Time	Username	Problem	Language	Result	Execution time	Memory
467810		spike1236	Evacuation plan (IZhO18_plan)	C++14	100 / 100	648 ms	53016 KiB

plan

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ll long long
#define ld long double
#define all(_v) _v.begin(), _v.end()
#define sz(_v) (int)_v.size()
#define pii pair <int, int>
#define pll pair <ll, ll>
#define veci vector <int>
#define vecll vector <ll>

const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, -1, 1};
const double PI = 3.1415926535897932384626433832795;
const double eps = 1e-9;
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;

const int MAXN = 1e5 + 10;
int n, m, k;
vector <pii> g[MAXN];
ll d[MAXN];
int up[MAXN][20];
ll mn[MAXN][20];
int tin[MAXN], tout[MAXN], tmr;

void dfs(int v, int p) {
    mn[v][0] = d[v];
    up[v][0] = p;
    for(int i = 1; i < 18; ++i) {
        if(up[v][i - 1]) {
            up[v][i] = up[up[v][i - 1]][i - 1];
            mn[v][i] = min(mn[up[v][i - 1]][i - 1], mn[v][i - 1]);
        }
    }
    tin[v] = ++tmr;
    for(auto to : g[v]) if(to.f != p) dfs(to.f, v);
    tout[v] = ++tmr;
}

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

int lca_(int v, int u) {
    if(upper(v, u)) return v;
    if(upper(u, v)) return u;
    for(int i = 17; i >= 0; --i)
        if(up[v][i] && !upper(up[v][i], u)) v = up[v][i];
    return up[v][0];
}

ll get_mn(int v, int lca) {
    if(v == lca) return d[v];
    assert(upper(lca, v));
    ll res = 1e18;
    for(int i = 17; i >= 0; --i) {
        if(up[v][i] && !upper(up[v][i], lca)) {
            res = min(res, mn[v][i]);
            v = up[v][i];
        }
    }
    return min(res, mn[v][0]);
}

int par[MAXN];

int get(int v) {
    return (v == par[v] ? v : par[v] = get(par[v]));
}

bool unite(int v, int u) {
    v = get(v), u = get(u);
    if(v == u) return 0;
    if(rand() & 1) par[v] = u;
    else par[u] = v;
    return 1;
}

void solve() {
    cin >> n >> m;
    vector <pii> ed;
    for(int i = 1; i <= m; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        ed.pb(mp(u, v));
        g[u].pb(mp(v, w));
        g[v].pb(mp(u, w));
    }
    for(int i = 1; i <= n; ++i) d[i] = 1e18;
    cin >> k;
    priority_queue <pair <ll, int> > q;
    for(int i = 1, v; i <= k; ++i) {
        cin >> v;
        q.push(mp(0ll, v));
        d[v] = 0;
    }
    while(!q.empty()) {
        auto v = q.top();
        q.pop();
        v.f = -v.f;
        if(v.f != d[v.s]) continue;
        for(auto to : g[v.s]) {
            if(d[to.f] > v.f + to.s) {
                d[to.f] = v.f + to.s;
                q.push(mp(-d[to.f], to.f));
            }
        }
    }
    sort(all(ed), [](const pii &a, const pii &b) {return (min(d[a.f], d[a.s]) < min(d[b.f], d[b.s]));});
    reverse(all(ed));
    for(int i = 0; i <= n; ++i) {
        par[i] = i;
        for(int j = 0; j < 18; ++j) mn[i][j] = 1e18;
        g[i].clear();
    }
    for(auto it : ed) {
        if(unite(it.f, it.s)) {
            g[it.f].pb(mp(it.s, 0));
            g[it.s].pb(mp(it.f, 0));
        }
    }
    dfs(1, 0);
    cin >> k;
    for(int cs = 1, u, v; cs <= k; ++cs) {
        cin >> u >> v;
        int LCA = lca_(u, v);
        cout << min({get_mn(u, LCA), get_mn(v, LCA), d[LCA]}) << '\n';
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int CNT_TESTS = 1;
    ///cin >> CNT_TESTS;
    for(int NUMCASE = 1; NUMCASE <= CNT_TESTS; ++NUMCASE) {
        solve();
        if(NUMCASE != CNT_TESTS) cout << '\n';
    }
    return 0;
}

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