Submission #1041837

#	Time	Username	Problem	Language	Result	Execution time	Memory
1041837		stdfloat	Swapping Cities (APIO20_swap)	C++17	0 / 100	2068 ms	12648 KiB

swap

#include <bits/stdc++.h>
#include "swap.h"
// #include "grader.cpp"
using namespace std;

using ll = long long;

#define ff  first
#define ss  second
#define pii pair<ll, ll>

ll n;

vector<vector<pii>> E;

void init(int N, int M, vector<int> U, vector<int> V, vector<int> W) {
    n = N;
    E.assign(n, {});
    for (ll i = 0; i < M; i++) {
        E[U[i]].push_back({V[i], W[i]});
        E[V[i]].push_back({U[i], W[i]});
    }
}

int getMinimumFuelCapacity(int X, int Y) {
    ll l = 0, r = (ll)1e9 + 1;
    while (l < r) {
        ll md = (l + r) >> 1;

        queue<ll> q;
        vector<bool> visX(n);
        vector<ll> p(n, -1);
        q.push(X); visX[X] = true;
        while (!q.empty()) {
            ll x = q.front(); q.pop();

            for (auto [i, w] : E[x]) {
                if (w <= md && !visX[i]) {
                    p[i] = x;
                    q.push(i);
                    visX[i] = true;
                }
            }
        }

        if (!visX[Y]) {
            l = md + 1;
            continue;
        }

        bool tr = false;
        vector<bool> visY(n);
        queue<pii> q1;
        q1.push({Y, -1}); visY[Y] = true;
        while (!q1.empty() && !tr) {
            auto [x, p] = q1.front(); q1.pop();
        
            for (auto [i, w] : E[x]) {
                if (w > md || i == p) continue;

                if (visY[i]) {
                    if (visX[i]) {
                        tr = true;
                        break;
                    }
                }
                else {
                    visY[i] = true;
                    q1.push({i, x});
                }
            }
        }

        ll x = Y;
        while (x != X && !tr) {
            x = p[x];

            ll cnt = 0;
            for (auto [i, w] : E[x]) {
                cnt += (w <= md);
            }

            tr = (cnt > 2);
        }

        if (!tr) l = md + 1;
        else r = md;
    }

    return (l == (ll)1e9 + 1 ? -1 : l);
}

• Subtask 1: 0 / 6
• Subtask 2: 0 / 7
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27