제출 #467786

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
467786		spike1236	Evacuation plan (IZhO18_plan)	C++14	0 / 100	304 ms	37972 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 bad[MAXN];
int up[MAXN][20];
ll mn[MAXN][20];
int tin[MAXN], tout[MAXN], tmr;
int dep[MAXN];

void dfs(int v, int p) {
    dep[v] = dep[p] + 1;
    mn[v][0] = d[v];
    up[v][0] = p;
    for(int i = 1; i < 20; ++i) {
        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 = 19; 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) {
    assert(upper(lca, v));
    ll res = 1e18;
    int len = dep[lca] - dep[v];
    for(int i = 19; i >= 0; --i)
        if(up[v][i] && ((len >> i) & 1)) {
            res = min(res, mn[v][i]);
            v = up[v][i];
        }
    return res;
}

bool cmp(const pii &a, const pii &b) {
    return (min(d[a.f], d[a.s]) < min(d[b.f], d[b.s]));
}

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

bool unite(int v, int u) {
    v = get(v), u = get(u);
    if(v == u) return 0;
    if(rand() & 1) tin[v] = u;
    else tin[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));
    }
    cin >> k;
    for(int i = 1, v; i <= k; ++i) {
        cin >> v;
        bad[v] = 1;
    }
    priority_queue <pair <ll, int> > q;
    for(int i = 1; i <= n; ++i) {
        if(bad[i]) q.push(mp(0ll, i));
        else d[i] = 1e18;
    }
    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), &cmp);
    reverse(all(ed));
    for(int i = 1; i <= n; ++i) g[i].clear(), tin[i] = i;
    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));
        }
    }
    for(int i = 0; i <= n; ++i) for(int j = 0; j < 20; ++j) mn[i][j] = 1e18;
    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)) << '\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;
}/**
9 12
1 9 4
1 2 5
2 3 7
2 4 3
4 3 6
3 6 4
8 7 10
6 7 5
5 8 1
9 5 7
5 4 12
6 8 2
2
4 7
5
1 6
5 3
4 8
5 8
1 5
*/

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46