제출 #980282

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
980282		vjudge1	가장 긴 여행 (IOI23_longesttrip)	C++17	25 / 100	13 ms	1112 KiB

longesttrip

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

#include <vector>
#define MP make_pair
#define f first
#define s second
#define mid ((l+r)>>1)
typedef long long ll;
using namespace std;

mt19937_64 rnd(286);

const int INF = (int)1e6;

bool conectados(int A, int B) {
    vector<int> a,b;
    a.push_back(A);
    b.push_back(B);
    return are_connected(a,b);
}

struct linea{
    deque <int> lin;
    linea(){}
    linea(int A) {
        lin.push_front(A);
    }
    void unir(linea &B, int NB, int NA) {
        if (NA == lin.front() && NB == B.lin.front()) {
            while (!B.lin.empty()) {
                lin.push_front(B.lin.front());
                B.lin.pop_front();
            }
            return;
        }
        if (NA == lin.front() && NB == B.lin.back()) {
            while (!B.lin.empty()) {
                lin.push_front(B.lin.back());
                B.lin.pop_back();
            }
            return;
        }
        if (NA == lin.back() && NB == B.lin.front()) {
            while (!B.lin.empty()) {
                lin.push_back(B.lin.front());
                B.lin.pop_front();
            }
            return;
        }
        if (NA == lin.back() && NB == B.lin.back()) {
            while (!B.lin.empty()) {
                lin.push_back(B.lin.back());
                B.lin.pop_back();
            }
            return;
        }
        return;
    }
};

vector <int> caso_base(int N) {
    vector <int> ans;
    ans.push_back(0);
    if (conectados(0, 1)) ans.push_back(1);
    return ans;
}

void dfs(int nodo, int p, vector <vector<int>> &g, vector <int> &ans) {
    ans.push_back(nodo);
    for (auto &it : g[nodo]) {
        if (it == p) continue;
        dfs(it, nodo, g, ans);
    }
    return;
}

int bin(int l, int r, vector <int> &ar, vector <int> &bus) {
    if (l == r) return ar[l];
    vector <int> aux;
    for (int i = l; i <= mid; i++) aux.push_back(ar[i]);
    if (are_connected(aux, bus)) return bin(l, mid, ar, bus);
    else return bin(mid + 1, r, ar, bus);
}

std::vector<int> longest_trip(int N, int D) {
    if (N <= 2) return caso_base(N);
    vector <linea> V;
    vector <int> ans;
    for (int i = 0; i < N; i++)
        V.push_back(linea(i));
    shuffle(V.begin(),V.end(),rnd);
    while (V.size() >= 3) {
        linea A = V.back();
        V.pop_back();
        linea B = V.back();
        V.pop_back();
        linea C = V.back();
        V.pop_back();
        if (conectados(A.lin.front(), B.lin.front())) {
            A.unir(B, B.lin.front(), A.lin.front());
            V.push_back(A);
            V.push_back(C);
        }
        else if (conectados(A.lin.front(), C.lin.front())) {
            A.unir(C, C.lin.front(), A.lin.front());
            V.push_back(A);
            V.push_back(B);
        }
        else {
            B.unir(C, C.lin.front(), B.lin.front());
            V.push_back(B);
            V.push_back(A);
        }
    }

    linea A = V[0], B = V[1];
    vector <int> VA, VB;
    while (!V[1].lin.empty()) {
        VB.push_back(V[1].lin.front());
        V[1].lin.pop_front();
    }
    while (!V[0].lin.empty()) {
        VA.push_back(V[0].lin.front());
        V[0].lin.pop_front();
    }

    if (VA.size() > VB.size()) return VA;
    return VB;

    if (!are_connected(VA,VB)) {
        if (VA.size() > VB.size()) return VA;
        return VB;
    }

    V[0] = A; V[1] = B;

    bool c1,c2,c3,c4;
    c1 = conectados(V[0].lin.front(), V[1].lin.front());
    c2 = conectados(V[0].lin.front(), V[1].lin.back());
    c3 = conectados(V[0].lin.back(), V[1].lin.back());
    c4 = conectados(V[0].lin.back(), V[1].lin.front());
    if (c1 || c2 || c3 || c4) {
        //if (c1) V[1].unir(V[0], V[0].lin.front(), V[1].lin.front());
        //else if (c2) V[1].unir(V[0], V[0].lin.front(), V[1].lin.back());
        //else if (c3) V[1].unir(V[0], V[0].lin.back(), V[1].lin.back());
        //else if (c4) V[1].unir(V[0], V[0].lin.back(), V[1].lin.front());

        //while (!V[1].lin.empty()) {
        //    ans.push_back(V[1].lin.front());
        //    V[1].lin.pop_front();
        //}
        return ans;
    }

    int ancla = bin(0, VA.size() - 1, VA, VB);
    vector <int> vancla;
    vancla.push_back(ancla);
    int ancla2 = bin(0, VB.size() - 1, VB, vancla);

    vector <vector<int>> g(N + 2);
    for (int i = 0; i < VA.size() - 1; i++) {
        g[VA[i]].push_back(VA[i + 1]);
        g[VA[i + 1]].push_back(VA[i]);
    }
    for (int i = 0; i < VB.size() - 1; i++) {
        g[VB[i]].push_back(VB[i + 1]);
        g[VB[i + 1]].push_back(VB[i]);
    }
    g[VA[VA.size() - 1]].push_back(VA[0]);
    g[VA[0]].push_back(VA[VA.size() - 1]);

    g[VB[VB.size() - 1]].push_back(VB[0]);
    g[VB[0]].push_back(VB[VB.size() - 1]);

    g[ancla].push_back(ancla2);
    g[ancla2].push_back(ancla);

    if (VA.size() != 1) {
        for (auto &it : g[ancla]) {
            if (it != ancla2) {
                dfs(it, -1, g, ans);
                break;
            }
        }
    }
    else {
        for (auto &it : g[ancla2]) {
            if (it != ancla) {
                dfs(it, -1, g, ans);
                break;
            }
        }
    }
    return ans;
}

컴파일 시 표준 에러 (stderr) 메시지

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:162:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  162 |     for (int i = 0; i < VA.size() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~
longesttrip.cpp:166:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  166 |     for (int i = 0; i < VB.size() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 25 / 25
• Subtask 4: 0 / 60