Submission #172684

#	Time	Username	Problem	Language	Result	Execution time	Memory
172684		muhammad_hokimiyon	Evacuation plan (IZhO18_plan)	C++14	100 / 100	966 ms	57104 KiB

plan

#include <bits/stdc++.h>

#pragma GCC optimize("Ofast")

#define fi first
#define se second
#define ll long long

using namespace std;

const int N = 2e5 + 7;
const int M = 23;
const ll mod = 998244353;

int n,m,q,k;
int a[N];
int d[N];
int p[N];
int cnt;
int dep[N];
int tin[N];
int tout[N];
int up[N][M];
int mn[N][M];
bool used[N];
vector < pair < int , int > > v[N];
vector < pair < int , int > > g[N];

void dfs( int x , int p , int z )
{
    up[x][0] = p;
    mn[x][0] = z;
    tin[x] = ++cnt;
    dep[x] = dep[p] + 1;
    for( int i = 1; i < M; i++ ){
        up[x][i] = up[up[x][i - 1]][i - 1];
        mn[x][i] = min(mn[x][i - 1] , mn[up[x][i - 1]][i - 1]);
    }
    for( auto y : g[x] ){
        if( y.fi != p ){
            dfs(y.fi , x , y.se);
        }
    }
    tout[x] = cnt;
}

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

int lca( int x , int y )
{
    if( upper(x , y) )return x;
    if( upper(y , x) )return y;
    for( int i = M - 1; i >= 0; i-- ){
        if( !upper(up[x][i] , y) ){
            x = up[x][i];
        }
    }
    return up[x][0];
}

int get( int x )
{
    return (p[x] == x ? x : p[x] = get(p[x]));
}

int get1( int x , int y )
{
    int ans = 1e9;
    for( int i = M - 1; i >= 0; i-- ){
        if( (1 << i) <= y ){
            y -= (1 << i);
            ans = min(ans , mn[x][i]);
            x = up[x][i];
        }
    }
    return ans;
}

void solve1()
{
    cin >> n >> m;
    for( int i = 1; i <= m; i++ ){
        int x,y,z;
        cin >> x >> y >> z;
        v[x].push_back({y , z});
        v[y].push_back({x , z});
    }
    for( int i = 1; i <= n; i++ ){
        d[i] = 1e9;
        p[i] = i;
    }
    cin >> k;
    set < pair < int , int > > s;
    for( int i = 1; i <= k; i++ ){
        cin >> a[i];
        s.insert({0 , a[i]});
        d[a[i]] = 0;
    }
    while( !s.empty() ){
        auto x = *s.begin();
        s.erase(s.begin());
        for( auto y : v[x.se] ){
            if( y.se + d[x.se] < d[y.fi] ){
                s.erase({d[y.fi] , y.fi});
                d[y.fi] = y.se + d[x.se];
                s.insert({d[y.fi] , y.fi});
            }
        }
    }
    vector < pair < int , int > > f;
    for( int i = 1; i <= n; i++ ){
        f.push_back({d[i] , i});
    }
    sort( f.rbegin() , f.rend() );
    for( int i = 0; i < (int)f.size(); i++ ){
        used[f[i].se] = true;
        for( auto y : v[f[i].se] ){
            if( used[y.fi] && get(y.fi) != get(f[i].se) ){
                g[f[i].se].push_back({y.fi,f[i].fi});
                g[y.fi].push_back({f[i].se,f[i].fi});
                p[get(f[i].se)] = get(y.fi);
            }
        }
    }
    dfs(1 , 1 , 0);
    cin >> q;
    while( q-- ){
        int x,y;
        cin >> x >> y;
        int gg = lca(x , y);
        cout << min( get1(x , dep[x] - dep[gg]) , get1(y , dep[y] - dep[gg]) ) << "\n";
    }
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    //freopen( "input.txt" , "r" , stdin );
    //freopen( "output.txt" , "w" , stdout );

    int cghf = 1;//cin >> cghf;
    while( cghf-- ){
        solve1();
    }
}

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