제출 #945894

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
945894		sysia	Evacuation plan (IZhO18_plan)	C++17	100 / 100	761 ms	67356 KiB

plan

//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << "'" << x << "'";}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

#define int long long
typedef pair<int, int> T;
const int oo = 1e18, oo2 = 1e9+7, K = 30;
const int mod = 998244353;

struct DSU{
    vector<int>rep, sz;

    DSU(int n){
        rep.resize(n+1);
        sz.resize(n+1);
    }

    void clear(){
        iota(rep.begin(), rep.end(), 0);
        sz.assign(sz.size(), 1);
    }

    int f(int a){
        return a == rep[a] ? a : rep[a] = f(rep[a]);
    }

    void u(int a, int b){
        a = f(a); b= f(b);
        if (a == b) return;
        if (sz[a] < sz[b]) swap(a, b);
        sz[a] += sz[b];
        rep[b] = a;
    }

    bool sameset(int a, int b){
        return f(a) == f(b);
    }
};

void solve(){
    int n, m; cin >> n >> m;
    vector<vector<T>>g(n+1);
    vector<T>edges;
    for (int i = 0; i<m; i++){
        int a, b, c; cin >> a >> b >> c;
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
        edges.emplace_back(a, b);
    }
    vector<int>dist(n+1, oo);
    int k; cin >> k;
    set<T>s;
    while (k--){
        int v; cin >> v;
        dist[v] = 0;
        s.insert({0, v});    
    }
    while ((int)s.size()){
        auto [d, v] = *s.begin();
        s.erase(s.begin());
        if (dist[v] < d) continue;
        for (auto [x, c]: g[v]){
            if (dist[x] > dist[v] + c){
                dist[x] = dist[v]+c;
                s.insert({dist[x], x});
            }
        }
    }
    debug(dist);
    vector<T>sweep;
    DSU dsu(n+2);
    for (int i = 0; i<m; i++){
        auto [a, b] = edges[i];
        sweep.emplace_back(min(dist[a], dist[b]), i);
    }
    sort(sweep.rbegin(), sweep.rend());
    debug(sweep);
    //max odleglosc ze jest sciezka miedzy nimi
    int q; cin >> q;
    vector<T>que(q);
    for (auto &[x, y]: que) cin >> x >> y;
    vector<int>L(q), R(q, oo2), ans(q, 0);
    while (1){
        bool any = 0;
        vector<T>tab;
        for (int i = 0; i<q; i++){
            if (R[i] >= L[i]){
                tab.emplace_back((L[i]+R[i])/2, i);
                any = 1;
            }
        }
        if (!any) break;
        dsu.clear();
        sort(tab.rbegin(), tab.rend());
        int ptr = -1;
        for (auto [mid, i]: tab){
            while (ptr + 1 < (int)sweep.size() && sweep[ptr+1].first >= mid){
                ptr++;
                auto [a, b] = edges[sweep[ptr].second];
                dsu.u(a, b);
            }
            if (dsu.sameset(que[i].first, que[i].second)){
                ans[i] = mid;
                L[i] = mid+1;
            } else R[i] = mid-1;
        }
    }
    for (auto x: ans) cout << x << "\n";
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
    //cin >> t;
    while (t--) solve();

    return 0;
}

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