Submission #982812

#	Time	Username	Problem	Language	Result	Execution time	Memory
982812		steveonalex	Evacuation plan (IZhO18_plan)	C++17	100 / 100	365 ms	53336 KiB

plan

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define ALL(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)

// mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng(1);
ll rngesus(ll l, ll r){return ((ull) rng()) % (r - l + 1) + l;}

ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}

ll LASTBIT(ll mask){return mask & (-mask);}
ll pop_cnt(ll mask){return __builtin_popcountll(mask);}
ll ctz(ll mask){return __builtin_ctzll(mask);}
ll clz(ll mask){return __builtin_clzll(mask);}
ll logOf(ll mask){return 63 - clz(mask);}

template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b){a = b; return true;}
        return false;
    }
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b){a = b; return true;}
        return false;
    }
template <class T>
    void printArr(T a, string separator = " ", string finish = "\n", ostream& out = cout){
        for(auto i: a) out << i << separator;
        out << finish;
    }
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

struct P{
    int i, w; 
    P(){}
    P(int _i, int _w){i = _i, w = _w;}
};

struct compare{
    bool operator () (P a, P b){return a.w > b.w;}
};

struct DSU{
    int n;
    vector<int> parent, sz;

    DSU(int _n){
        n = _n;
        parent.resize(n+1); sz.resize(n+1, 1);
        for(int i = 1; i<=n; ++i) parent[i] = i;
    }

    int find_set(int u){return (u == parent[u]) ? u : (parent[u] = find_set(parent[u]));}
    bool join_set(int u, int v){
        u = find_set(u), v = find_set(v);
        if (u != v){
            if (sz[u] < sz[v]) swap(u, v);
            parent[v] = u;
            sz[u] += sz[v];
            return true;
        }
        return false;
    }
};

const int N  = 1e5 + 69, INF = 1e9 + 69, LOG_N = 17;

int n, m; 
vector<P> graph[N];
vector<pair<int, int>> tree[N];
int dis[N];


int h[N], parent[N][LOG_N], min_w[N][LOG_N];
void dfs(int u, int p){
    h[u] = h[p] + 1;
    for(int j = 1; MASK(j) < h[u]; ++j){
        int prev = parent[u][j-1];
        parent[u][j] = parent[prev][j-1];
        min_w[u][j] = min(min_w[u][j-1], min_w[prev][j-1]);
    }
    for(pair<int, int> v: tree[u]) if (v.first != p){
        parent[v.first][0] = u;
        min_w[v.first][0] = v.second;
        dfs(v.first, u);
    }
}

int LCA(int u, int v){
    if (h[u] < h[v]) swap(u, v);
    int ans = INF;
    int diff = h[u] - h[v];
    for(int j = 0; j< LOG_N; ++j) if (GETBIT(diff, j)) {
        minimize(ans, min_w[u][j]);
        u = parent[u][j];
    }
    if (u == v) return ans;
    for(int j= LOG_N - 1; j>=0; --j) if (parent[u][j] != parent[v][j]){
        minimize(ans, min(min_w[u][j], min_w[v][j]));
        u = parent[u][j], v = parent[v][j];
    }
    minimize(ans, min(min_w[u][0], min_w[v][0]));
    return ans;
}

int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> m;
    for(int i =0; i<m; ++i){
        int u, v, w; cin >> u >> v >> w;
        graph[u].push_back(P(v, w));
        graph[v].push_back(P(u, w));
    }

    int k; cin >> k;
    vector<int> npp(k);
    for(int i= 0; i<k; ++i)
        cin >> npp[i];

    remove_dup(npp);

    k = npp.size();

    priority_queue<P, vector<P>, compare> pq;
    for(int i = 1; i<=n; ++i) dis[i] = INF;
    for(int i: npp) {
        dis[i] = 0;
        pq.push(P(i, 0));
    }
    while(pq.size()){
        P u = pq.top(); pq.pop();
        for(P v: graph[u.i]) 
            if (minimize(dis[v.i], dis[u.i] + v.w))
                pq.push(P(v.i, dis[v.i]));
    }

    vector<array<int, 3>> edging;
    for(int i = 1; i<=n; ++i) for(P j: graph[i]) if (i < j.i){
        edging.push_back({{i, j.i, min(dis[i], dis[j.i])}});
    }
    sort(ALL(edging), [](array<int, 3> x, array<int, 3> y){return x[2] > y[2];});

    DSU mst(n);
    for(auto i: edging) if (mst.join_set(i[0], i[1])){
        int u = i[0], v = i[1], w = i[2];
        tree[u].push_back({v, w});
        tree[v].push_back({u, w});
    }

    dfs(1, 1);

    int q; cin >> q;
    while(q--){
        int u, v; cin >> u >> v;
        int ans = LCA(u, v);
        cout << ans << "\n";
    }

    return 0;
}

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