Submission #338499

#	Time	Username	Problem	Language	Result	Execution time	Memory
338499		Dilshod_Imomov	Evacuation plan (IZhO18_plan)	C++17	35 / 100	3206 ms	76652 KiB

plan

# include <bits/stdc++.h>
# define speed ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
# define int long long
# define fi first
# define se second
 
using namespace std;
 
const int N = 2e6 + 7;
const int mod = 1e9 + 7;

vector < pair < int, int > > adj[N];
int dist[N], n, m, go;
bool used[N];

void dfs( int v, int dest, int x ) {
    used[v] = 1;
    if ( v == dest ) {
        go = 1;
        return;
    }
    for ( auto pr: adj[v] ) {
        int u = pr.fi;
        if ( !used[u] && dist[u] >= x ) {
            dfs( u, dest, x );
        }
    }
}

bool can( int a, int b, int x ) {
    go = 0;
    for ( int i = 1; i <= n; i++ ) {
        used[i] = 0;
    }
    if ( dist[a] < x ) {
        return 0;
    }
    dfs( a, b, x );
    return go;
}

int32_t main() {
    speed;
    cin >> n >> m;
    for ( int i = 1; i <= m; i++ ) {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back( { v, w } );
        adj[v].push_back( { u, w } );
    }
    for ( int i = 1; i <= n; i++ ) {
        dist[i] = 1e9;
    }
    int k;
    cin >> k;
    set < pair < int, int > > q;
    for ( int i = 1; i <= k; i++ ) {
        int x;
        cin >> x;
        q.insert( { 0, x } );
        dist[x] = 0;
    }
    while ( !q.empty() ) {
        int v = q.begin()->se;
        q.erase( q.begin() );
        for ( auto pr: adj[v] ) {
            int u = pr.fi, w = pr.se;
            if ( dist[u] > dist[v] + w ) {
                q.erase( { dist[u], u } );
                dist[u] = dist[v] + w;
                q.insert( { dist[u], u } );
            }
        }
    }
    int qr;
    cin >> qr;
    while ( qr-- ) {
        int a, b, ok = 0;
        cin >> a >> b;
        for ( auto pr: adj[a] ) {
            int u = pr.fi;
            if (u == b) {
                cout << min( dist[u], dist[a] ) << '\n';
                ok = 1;
            }
        }
        if ( ok ) {
            continue;
        }
        int l = 0, r = 1000, ans = 0;
        while ( l <= r ) {
            int mid = (l + r) / 2;
            if ( can( a, b, mid ) ) {
                ans = mid;
                l = mid + 1;
            }
            else {
                r = mid - 1;
            }
        }
        cout << ans << '\n';
    }
}

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