제출 #1084501

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1084501		SamueleVid	수천개의 섬 (IOI22_islands)	C++17	10 / 100	372 ms	685960 KiB

islands

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

// constexpr int MAXN = 1e5 + 5;
constexpr int MAXN = 1e3 + 5;
constexpr int MAXM = 2e5 + 5;

// vector<pair<int, int>> adj[MAXN]; // nodo, barca
stack<int> adj[MAXN][MAXN];
bool v[MAXN];
vector<int> barche;
vector<int> barche_res;
vector<int> nodi;
int N;
bool fatto = true;

variant<bool, vector<int>> n_two(int N, int M, vector<int> U, vector<int> V) {
    vector<int> el_primo;
    vector<int> el_secondo;
    for (int i = 0; i < M; i ++) {
        if (U[i] == 0) el_primo.push_back(i);
        if (U[i] == 1) el_secondo.push_back(i);
    }

    if (el_primo.size() >= 2 && el_secondo.size() >= 1) {
        int a = el_primo[0];
        int b = el_secondo[0];
        int c = el_primo[1];
        vector<int> res = {a, b, c, a, b, c};
        return res;
    }

    return false;
}

variant<bool, vector<int>> subtask_two(int N, int M, vector<int> U, vector<int> V) {
    int a, b, c, d, e, f;
    for (int i = 0; i < M; i ++) {
        if (U[i] == 0 && V[i] == 1) a = i;
        if (U[i] == 1 && V[i] == 0) b = i;
        if (U[i] == 1 && V[i] == 2) c = i;
        if (U[i] == 2 && V[i] == 1) d = i;
        if (U[i] == 2 && V[i] == 0) e = i;
        if (U[i] == 0 && V[i] == 2) f = i;
    }

    vector<int> res = {a, c, e, f, d, b, e, c, a, b, d, f};
    return res;
}



void dfs(int u) {
    if (fatto) return;
    nodi.push_back(u);
    if (v[u]) {
        // minchia ora comincia il bello
        int primo_u = -1;
        for (int i = 0; i < nodi.size(); i ++) {
            if (nodi[i] == u) {
                primo_u = i;
                break;
            }
        }
        assert(primo_u != -1);

        int prec = u;
        for (int k = 0; k < 2; k ++) {
            for (int i = primo_u + 1; i < nodi.size(); i ++) {
                int barca = adj[prec][i].top(); adj[prec][i].pop();
                adj[i][prec].push(barca);
                
                barche.push_back(barca);
            }
        }

        for (int i = primo_u - 1; i >= 0; i --) {
            int barca = adj[prec][i].top(); adj[prec][i].pop();
            adj[i][prec].push(barca);
            
            barche.push_back(barca);
        }
        barche_res = barche;

        fatto = true;
        return;
    }
    if (fatto) return;
    v[u] = 1;

    for (int i = 0; i < N; i ++) {
        if (adj[u][i].empty()) continue;

        int barca = adj[u][i].top(); adj[u][i].pop();
        adj[i][u].push(barca);
        
        barche.push_back(barca);
        dfs(u);
        if (fatto) return;
        barche.pop_back();

        adj[i][u].pop();
        adj[u][i].push(barca);
    }
}

variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) {
    :: N = N;
    if (N <= 2) return n_two(N, M, U, V);
    if (N <= 400) return subtask_two(N, M, U, V);

    fill(v, v + MAXN, 0);
    for (int i = 0; i < M; i ++) {
        adj[U[i]][V[i]].push(i);
    }

    dfs(0);

    if (fatto) return barche_res;
    else return false;
}

컴파일 시 표준 에러 (stderr) 메시지

islands.cpp: In function 'void dfs(int)':
islands.cpp:59:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |         for (int i = 0; i < nodi.size(); i ++) {
      |                         ~~^~~~~~~~~~~~~
islands.cpp:69:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   69 |             for (int i = primo_u + 1; i < nodi.size(); i ++) {
      |                                       ~~^~~~~~~~~~~~~
islands.cpp: In function 'std::variant<bool, std::vector<int, std::allocator<int> > > subtask_two(int, int, std::vector<int>, std::vector<int>)':
islands.cpp:47:58: warning: 'f' may be used uninitialized in this function [-Wmaybe-uninitialized]
   47 |     vector<int> res = {a, c, e, f, d, b, e, c, a, b, d, f};
      |                                                          ^
islands.cpp:47:58: warning: 'e' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:47:58: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:47:58: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:47:58: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:47:58: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45