Submission #558546

#	Time	Username	Problem	Language	Result	Execution time	Memory
558546		proma	Swapping Cities (APIO20_swap)	C++17	0 / 100	2077 ms	17240 KiB

swap

#include "swap.h"
#include <bits/stdc++.h>

using namespace std;

const int N = 1e5+5;

int n, m, used[N], flag;
vector <pair <int, int>> g[N];
vector <int> val;

void init(int N, int M, vector<int> U, vector<int> V, vector<int> W) {
    n = N;
    m = M;
    for (int i = 0; i < M; i ++) {
        g[U[i]].push_back({V[i], W[i]});
        g[V[i]].push_back({U[i], W[i]});
        val.push_back(W[i]);
    }
    sort(val.begin(), val.end());
}

void dfs(int v, int p, int k, int x, int y) {
    used[v] = 1;
//    cerr << "v = " << v << endl;
    if (v != x and v != y and g[v].size() > 2) flag = 1;
    for (auto i: g[v]) {
        if (i.second > k or i.first == p) continue;
        if (used[i.first]) flag = 1;
        else dfs(i.first, v, k, x, y);
    }
}

int getMinimumFuelCapacity(int X, int Y) {
    int l = 0, r = m - 1, best = -1;
    while (l <= r) {
        int mid = (l + r) / 2;
//        cerr << "mid = " << mid << endl;
        flag = 0;
        memset(used, 0, sizeof(used));
        dfs(X, 0, val[mid], X, Y);
//        cerr << "used[Y] = " << used[Y] << endl;
//        cerr << "flag = " << flag << endl;
        if (used[Y] and flag) {
            best = val[mid];
            r = mid - 1;
        }
        else {
            l = mid + 1;
        }
    }
    return best;
}

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