Submission #1183533

#	Time	Username	Problem	Language	Result	Execution time	Memory
1183533		PagodePaiva	Thousands Islands (IOI22_islands)	C++20	Compilation error	0 ms	0 KiB

islands

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

using namespace std;

const int N = 1010;
const int M = 200010;
vector <int> g[N];
int mark[M];
int mark_ver[N];
bool res = false;
void dfs(int v, int p, int idx){
    mark_ver[v] = 1;
    mark[idx] = 1;
    for(auto [x, i] : g[v]){
        if(mark_ver[x] == 1 and mark[i] == 0){
            res = true;
            return;
        }
        if(x == p)
            continue;
        dfs(x, v, i);
    }
    return;
}

std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V) {
    for(int i = 0;i < M;i++){
        g[U[i]].push_back({V[i], i/2});

    }  
    vector <int> ans = {};
    if(g[0].size() >= 2){
        return ans;
    }
    dfs(0, 0, M-1);
    if(res) return ans;
    return res;
}

Compilation message (stderr)

islands.cpp: In function 'void dfs(int, int, int)':
islands.cpp:17:14: error: cannot decompose non-array non-class type 'int'
   17 |     for(auto [x, i] : g[v]){
      |              ^~~~~~
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:32:26: error: no matching function for call to 'std::vector<int>::push_back(<brace-enclosed initializer list>)'
   32 |         g[U[i]].push_back({V[i], i/2});
      |         ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
In file included from /usr/include/c++/11/vector:67,
                 from islands.h:2,
                 from islands.cpp:1:
/usr/include/c++/11/bits/stl_vector.h:1187:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = int; _Alloc = std::allocator<int>; std::vector<_Tp, _Alloc>::value_type = int]'
 1187 |       push_back(const value_type& __x)
      |       ^~~~~~~~~
/usr/include/c++/11/bits/stl_vector.h:1187:35: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const value_type&' {aka 'const int&'}
 1187 |       push_back(const value_type& __x)
      |                 ~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/11/bits/stl_vector.h:1203:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(std::vector<_Tp, _Alloc>::value_type&&) [with _Tp = int; _Alloc = std::allocator<int>; std::vector<_Tp, _Alloc>::value_type = int]'
 1203 |       push_back(value_type&& __x)
      |       ^~~~~~~~~
/usr/include/c++/11/bits/stl_vector.h:1203:30: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'std::vector<int>::value_type&&' {aka 'int&&'}
 1203 |       push_back(value_type&& __x)
      |                 ~~~~~~~~~~~~~^~~