Submission #722672

#	Time	Username	Problem	Language	Result	Execution time	Memory
722672		bin9638	Thousands Islands (IOI22_islands)	C++17	Compilation error	0 ms	0 KiB

islands

#include <bits/stdc++.h>

#ifndef SKY
#include "islands.h"
#endif // SKY

using namespace std;

#define N 100010
#define ll long long
#define fs first
#define sc second
#define ii pair<int,int>
#define pb push_back

int sz[N],n,m,ktr[N],ans=0,pos[N],num[N],low[N],times,dem;
vector<int>g[N],edge[N];
stack<int>st;

void visit(int u)
{
    num[u]=low[u]=++times;
    st.push(u);
    for(auto v:g[u])
        if(num[v]!=0)
        {
            low[u]=min(low[u],num[v]);
        }else
        {
            visit(v);
            low[u]=min(low[u],low[v]);
        }
    if(low[u]==num[u])
    {
        int k;
        dem++;
        do{
            k=st.top();
            st.pop();
            num[k]=low[k]=1e9;
            pos[k]=dem;
            sz[dem]++;
        }while(k!=u);
    }
}

void DFS(int u)
{
    ktr[u]=1;
    if(sz[u]>=2)
        ans=1;
    for(auto v:edge[u])
        if(ktr[v]==0)
            DFS(v);
}

#ifdef SKY
vector<int>
#endif // SKY
#ifndef SKY
variant<bool, vector<int>>
#endif // SKY
find_journey(int NNN, int MMM, vector<int> canh_fs, vector<int> canh_sc)
{
    n=NNN;
    m=MMM;
    for(int i=0;i<m;i++)
    {
        int u=canh_fs[i],v=canh_sc[i];
        g[u].pb(v);
    }
    for(int i=0;i<n;i++)
        if(num[i]==0)
            visit(i);
    for(int i=0;i<m;i++)
    {
        int u=canh_fs[i],v=canh_sc[i];
        if(pos[u]!=pos[v])
            edge[pos[u]].pb(pos[v]);
    }
    DFS(pos[0]);
    #ifdef SKY
    return{ans};
    #endif // SKY
    #ifndef SKY
    return ans;
    #endif // SKY
}

#ifdef SKY
int main()
{
    freopen("A.inp","r",stdin);
    freopen("A.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

    return 0;
}
#endif

Compilation message (stderr)

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:86:12: error: could not convert 'ans' from 'int' to 'std::variant<bool, std::vector<int, std::allocator<int> > >'
   86 |     return ans;
      |            ^~~
      |            |
      |            int