제출 #1028236

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1028236		42kangaroo	수천개의 섬 (IOI22_islands)	C++17	10 / 100	20 ms	5328 KiB

islands

#include "islands.h"

#include <variant>
#include <vector>
#include "bits/stdc++.h"

using namespace std;

using g_t = vector<vector<pair<int,int>>>;

int dfs(int n, int p, g_t& g, vector<bool>& vis, vector<int>& re) {
	vis[n] = true;
	for (auto [ne, nu]: g[n]) {
		if (vis[ne]) {
			re.push_back(nu);
			return ne;
		}
		int res = dfs(ne, nu, g, vis, re);
		if (re.empty()) continue;
		re.push_back(nu);
		if (res == n) {
			re.push_back(-1);
			return -2;
		}
		return res;
	}
	return -2;
}

std::variant<bool, std::vector<int>> find_journey(
		int N, int M, std::vector<int> U, std::vector<int> V) {
	if (N == 2) {
		vector<int> s0, s1;
		for (int i = 0; i < M; ++i) {
			if (U[i] == 0) s0.push_back(i);
			else s1.push_back(i);
		}
		if (s0.size() >= 2 && s1.size() >= 1) {
			return vector<int>{s0[0], s1[0], s0[1], s0[0], s1[0], s0[1]};
		} else return false;
	}
	g_t g(N);
	int s01, s10, s21, s02;
	for (int i = 0; i < M; ++i) {
		if (U[i] == 0 && V[i] == 1) s01 = i;
		if (U[i] == 1 && V[i] == 0) s10 = i;
		if (U[i] == 2 && V[i] == 1) s21 = i;
		if (U[i] == 0 && V[i] == 2) s02 = i;
	}
	return vector<int>{s02, s21, s10, s01, s21, s02, s10, s01};
}

컴파일 시 표준 에러 (stderr) 메시지

islands.cpp: In function 'std::variant<bool, std::vector<int, std::allocator<int> > > find_journey(int, int, std::vector<int>, std::vector<int>)':
islands.cpp:50:59: warning: 's02' may be used uninitialized in this function [-Wmaybe-uninitialized]
   50 |  return vector<int>{s02, s21, s10, s01, s21, s02, s10, s01};
      |                                                           ^
islands.cpp:50:59: warning: 's21' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:50:59: warning: 's10' may be used uninitialized in this function [-Wmaybe-uninitialized]
islands.cpp:50:59: warning: 's01' 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