# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1221163 | hmms127 | Connecting Supertrees (IOI20_supertrees) | C++20 | 0 ms | 0 KiB |
#include "supertrees.h"
#include <vector>
using namespace std;
int frq[1005];
#define pb push_back
struct DSU{
vector<int>par,sz;
void init(int n){
par.resize(n+1);sz.resize(n+1);
for(int i=0;i<n;i++)par[i]=i,sz[i]=1;
}
int root(int u){
return par[u]==u ? u:par[u]=root(par[u]);
}
bool merge(int u,int v){
int ru=root(u),rv=root(v);
frq[u]++;
frq[v]++;
if(ru==rv)return 0;
if(sz[ru]>sz[rv])swap(sz[ru],sz[rv]);
par[ru]=rv;sz[rv]+=sz[ru];
return 1;
}
};
int dfs(int node,int target,vector<vector<int>>& adj,vector<bool>& visited) {
if(node==target)return 1;
visited[node]=true;
int paths=0;
for (int v:adj[node]) {
if(!visited[v])paths+=countPaths(v,target,adj,visited);
}
visited[node]=false;
return paths;
}
int construct(std::vector<std::vector<int>> p) {
int n=p[0].size();
vector<vector<int>>v(n,vector<int>(n,0));
DSU d,d1;d.init(n);d1.init(n);
vector<int>adj[n];
for(int i=0;i<n;i++){
for(int j=i+1;j<n;j++){
if(i==j)continue;
if(p[i][j]){
if(d.root(i)==d.root(j)){d1.merge(i,j);}
else d.merge(i,j);
v[i][j]=1;
v[j][i]=1;
adj[i].pb(j);adj[j].pb(i);
}
}
}
for(int i=0;i<n;i++){
for(int j=i+1;j<n;j++){
if(p[i][j]==0&&d.root(i)==d.root(j))return 0;
}
}
for(int i=0;i<n;i++){
for(int j=i+1;j<n;j++){
vector<int> v(n,0);
if(p[i][j]==2&&dfs(i,j,adj,v)!=2)return 0;
}
}
build(v);
return 1;
}