Submission #162869

#	Time	Username	Problem	Language	Result	Execution time	Memory
162869		mrboorger	Evacuation plan (IZhO18_plan)	C++17	54 / 100	636 ms	20872 KiB

plan

//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#include <bits/stdc++.h>

#define pb push_back
#define F first
#define S second
#define ll long long
#define ull unsigned long long
#define ld long double
#define sqr(x) (x) * (x)

using namespace std;
using namespace __gnu_pbds;

const int maxn = 1e5 + 2;
const int inf = 1e9 + 33333;

vector <pair <int, int>> g[maxn];
bool used[maxn];
int d[maxn];
int mid;

void dfs(int v)
{
    used[v] = true;
    for(pair <int, int> to : g[v])
        if(!used[to.F] && d[to.F] >= mid) dfs(to.F);
    return;
}


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

    int n, m;
    cin >> n >> m;
    for(int i = 0; i < m; ++i)
    {
        int x, y, z;
        cin >> x >> y >> z;
        --x;
        --y;
        g[x].pb({y, z});
        g[y].pb({x, z});
    }
    fill(d, d + n, inf);
    priority_queue <pair <int, int>, vector <pair <int, int>>, greater<pair <int, int>>> q;
    int k;
    cin >> k;
    for(int i = 0; i < k; ++i)
    {
        int x;
        cin >> x;
        --x;
        d[x] = 0;
        q.push({0, x});
    }
    while(!q.empty())
    {
        int val = q.top().F;
        int v = q.top().S;
        q.pop();
        if (val > d[v]) continue;
        for(pair <int, int> to : g[v])
        {
            if (d[to.F] > val + to.S)
            {
                d[to.F] = val + to.S;
                q.push({val + to.S, to.F});
            }
        }
    }
    int Q;
    cin >> Q;
    if (1ll * n * Q < 2e6 + 1)
        for(int ii = 0; ii < Q; ++ii)
        {
            int x, y;
            cin >> x >> y;
            --x;
            --y;
            int l = 0, r = 1e9;
            int ans = 0;
            while(l <= r)
            {
                mid = (l + r) / 2;
                fill(used, used + n, false);
                if (d[x] >= mid) dfs(x);
                if (used[y])
                {
                    ans = max(ans, mid);
                    l = mid + 1;
                }
                else
                {
                    r = mid - 1;
                }
            }
            cout << ans << '\n';
        }
    else
        for(int ii = 0; ii < Q; ++ii)
        {
            int x, y;
            cin >> x >> y;
            --x;
            --y;
            cout << min(d[x], d[y]) << '\n';
        }
    return 0;
}

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