# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
826386 | alvingogo | Thousands Islands (IOI22_islands) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "islands.h"
#include <bits/stdc++.h>
#include <variant>
#define fs first
#define sc second
using namespace std;
vector<vector<pair<int,int> > > e;
vector<int> dep,fa;
vector<int> ans;
int dfs(int r,int f){
dep[r]=dep[f]+1;
fa[r]=f;
for(auto h:e[r]){
if(dep[h.fs]==-1){
if(dfs(h.fs,r)){
return 1;
}
}
else if(dep[h.fs]>=0){
vector<int> bz;
for(int i=0;i!=h.fs;){
for(auto w:e[i]){
if(dep[w.fs]==dep[i]+1){
bz.push_back(w.sc);
i=w.fs;
break;
}
}
}
vector<int> cz,dz;
for(int i=h.fs;i!=r;){
for(auto w:e[i]){
if(dep[w.fs]==dep[i]+1){
cz.push_back(w.sc);
dz.push_back(w.sc+1);
i=w.fs;
break;
}
}
}
ans.insert(ans.end(),bz.begin(),bz.end());
ans.insert(ans.end(),cz.begin(),cz.end());
ans.insert(ans.end(),dz.begin(),dz.end());
reverse(bz.begin(),bz.end());
reverse(cz.begin(),cz.end());
reverse(dz.begin(),dz.end());
ans.insert(ans.end(),cz.begin(),cz.end());
ans.insert(ans.end(),dz.begin(),dz.end());
ans.insert(ans.end(),bz.begin(),bz.end());
return 1;
}
}
dep[h.fs]=-2;
return 0;
}
variant<bool, vector<int>> find_journey(
int n, int m, vector<int> u, vector<int> v) {
e.resize(n);
fa.resize(n);
dep.resize(n,-1);
for(int i=0;i<m;i+=2){
e[u[i]].push_back({v[i],i});
}
if(!dfs(0,0)){
return false;
}
return ans;
}