Submission #947305

#	Time	Username	Problem	Language	Result	Execution time	Memory
947305		AlphaMale06	Evacuation plan (IZhO18_plan)	C++14	0 / 100	201 ms	57996 KiB

plan

#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define F first
#define S second
#define int long long
const int N = 1e5+3;

vector<pair<int, pair<int, int>>> edges;
vector<pair<int, int>> adj[N], g[N];
int dist[N], mark[N], p[N], sz[N], tin[N], tout[N];
int up[N][17], cost[N][17];
int timer=-1;

int find(int v){
    if(p[v]==v)return v;
    return p[v]=find(p[v]);
}

void merge(int u, int v){
    u=find(u);
    v=find(v);
    if(u==v)return;
    if(sz[u]<sz[v])swap(u, v);
    sz[u]+=sz[v];
    p[v]=u;
}

void dfs(int v, int par){
    tin[v]=++timer;
    for(int i=1; i<17; i++){
        up[v][i]=up[up[v][i-1]][i-1];
        cost[v][i]=min(cost[v][i-1], cost[up[v][i-1]][i-1]);
    }
    for(auto to : adj[v]){
        if(to.F!=par){
            up[to.F][0]=v;
            cost[to.F][0]=to.S;
            dfs(to.F, v);
        }
    }
    tout[v]=++timer;
}

bool isanc(int u, int v){
    if(tin[u]<=tin[v] && tout[u]>=tout[v])return 1;
    return 0;
}

int lca(int u, int v){
    if(isanc(v, u))swap(u, v);
    int mx=1e9;
    if(!isanc(u, v)){
        for(int i=16; i>=0; i--){
            if(!isanc(up[u][i], v)){
                mx=min(mx, cost[u][i]);
                u=up[u][i];
            }
        }
        mx=min(mx, cost[u][0]);
        u=up[u][0];
    }
    for(int i=16; i>=0; i--){
        if(!isanc(v, u)){
            mx=min(mx, cost[v][i]);
            v=up[v][i];
        }
    }
    mx=min(mx, cost[v][0]);
    return mx;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    for(int i=0; i< m; i++){
        int a, b, c;
        cin >> a >> b >> c;
        g[a].pb({b, c});
        g[b].pb({a, c});
        edges.pb({c, {a, b}});
    }
    int k;
    cin >> k;
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    for(int i=0; i<=n; i++)dist[i]=1e9;
    for(int i=0; i< k; i++){
        int a;
        cin >> a;
        pq.push({0, a});
        dist[a]=0;
    }
    while(pq.size()){
        auto pr = pq.top();
        pq.pop();
        int v = pr.S;
        if(mark[v])continue;
        for(auto to : g[v]){
            if(mark[to.F])continue;
            if(to.S+pr.F < dist[to.F]){
                dist[to.F]=to.S+pr.F;
                pq.push({dist[to.F], to.F});
            }
        }
    }
    for(auto & e : edges){
        e.F = min(dist[e.S.F], dist[e.S.S]);
    }
    sort(edges.begin(), edges.end());
    reverse(edges.begin(), edges.end());
    for(int i=1; i<=n; i++){
        p[i]=i;
        sz[i]=1;
    }
    for(auto e : edges){
        if(find(e.S.F)!=find(e.S.S)){
            merge(e.S.F, e.S.S);
            adj[e.S.F].pb({e.S.S, e.F});
            adj[e.S.S].pb({e.S.F, e.F});
        }
    }
    up[1][0]=1;
    cost[1][0]=1e9;
    dfs(1, 0);
    int q;
    cin >> q;
    while(q--){
        int a, b;
        cin >> a >> b;
        cout << lca(a, b) << '\n';
    }
}

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