Submission #1216730

#	Time	Username	Problem	Language	Result	Execution time	Memory
1216730		JooDdae	Towns (IOI15_towns)	C++20	0 / 100	21 ms	8184 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
using namespace std;

int hubDistance(int N, int sub) {
    vector<vector<int>> D(N, vector<int>(N, 0));
    for(int i=1;i<N;i++) D[0][i] = D[i][0] = getDistance(0, i);
    int E = max_element(D[0].begin(), D[0].end()) - D[0].begin();
    for(int i=0;i<N;i++) if(i != E) D[E][i] = D[i][E] = getDistance(E, i);
    int X = max_element(D[E].begin(), D[E].end()) - D[E].begin();

    vector<int> C(N, 0), mp(1001001, 0);
    for(int i=0;i<N;i++) mp[C[i] = (D[E][i]+D[0][E] - D[0][i])/2]++;
    
    int R = 1e9, h1 = -1, h2 = -1;
    for(int i=0;i<N;i++) if(i != E && C[i] <= C[X]) {
        auto r = max(C[i], D[E][X]-C[i]);
        if(R > r) R = r, h1 = i, h2 = -1;
        else if(R == r && C[h1] != C[i]) h2 = i;
    }

    vector<int> c(2, 0);
    for(int i=0;i<N;i++) c[C[i] > C[h1]]++;
    if(h2 != -1) {
        if(max(c[0], c[1]) <= N/2) return R;
        if(c[0] <= N/2) h1 = h2, c[0] += mp[C[h2]], c[1] -= mp[C[h2]];
    }
    c[0] -= mp[C[h1]];
    if(max(c[0], c[1]) > N/2) return -R;

    vector<int> v;
    for(int i=0;i<N;i++) if(C[i] == C[h1]) v.push_back(i);

    vector<vector<int>> same(N, vector<int>(N, -1));
    auto check = [&](int x, int y) {
        if(x == y) return 1;
        if(same[x][y] != -1) return same[x][y];
        D[x][y] = D[y][x] = getDistance(x, y);
        return same[y][x] = same[x][y] = D[E][x] + D[E][y] != D[x][y] + C[h1]*2;
    };

    int c1 = 0, c2 = 0;
    // vector<int> S;
    // vector<vector<int>> L;
    // for(auto x : v) {
    //     S.push_back(x);
    //     if(check(S[0], x)) c1++;
    //     else if(++c2 == c1) L.push_back(S), S.clear(), c1 = c2 = 0;
    // }

    // cout << E << " " << h1 << "\n";
    // for(auto x : v) {
    //     for(auto y : v) {
    //         cout << x << " " << y << " " << check(x, y) << '\n';
    //         cout << "   " << D[E][x] << " " << D[E][y] << " " << D[x][y] << " " << C[h1] << "\n";
    //     }
    // }

    // for(auto V : L) {
    //     for(auto x : V) {
    //         if(check(S[0], V[0])) c1 += check(V[0], x);
    //         else if(!check(V[0], x)) c1 += check(S[0], x);
    //     }
    // }
    // return c1 <= N/2 ? R : -R;

    for(auto S : v) {
        c1 = 0;
        for(auto x : v) c1 += check(S, x);
        if(c1 > N/2) return -R;
    }
    return R;
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 12
• Subtask 3: 0 / 13
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 39