Submission #488037

#	Time	Username	Problem	Language	Result	Execution time	Memory
488037		SlavicG	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	228 ms	26192 KiB

supertrees

#include "supertrees.h"
#include "bits/stdc++.h"
using namespace std;
 
#define ll long long
 
#define       forn(i,n)              for(int i=0;i<n;i++)
#define          all(v)              v.begin(), v.end()
#define         rall(v)              v.rbegin(),v.rend()
 
#define            pb                push_back
#define          sz(a)               (int)a.size()
 
struct DSU{
    int n;
    vector<int> par, s;
 
    DSU(int N){
        n = N;
        s.assign(n, 1), par.resize(n);
        iota(all(par), 0);
    }
 
    int get(int a){
        return par[a] = (a == par[a] ? a : get(par[a]));
    }
 
    void uni(int a, int b){
        a = get(a), b = get(b);
        if(s[a] > s[b])swap(a, b);
        par[a] = b, s[b] += s[a];
    }
 
    int get_size(int a){
        return s[get(a)];
    }
    bool same_set(int a, int b){
        return get(a) == get(b);
    }
};
 
const int N = 1005;
vector<int> adj[N], adj2[N];
vector<int> component;
bool vis[N];

void dfs(int u){
    component.pb(u);
    vis[u] = true;
    for(int v: adj[u])if(!vis[v])dfs(v);
}
 
int construct(vector<vector<int>> p){
    int n = sz(p);
    vector<vector<int>> ans(n, vector<int>(n, 0));
    
    forn(i,n)adj[i].clear(), adj2[i].clear();
    DSU d(n);
    DSU fuck(n);    
    for(int i = 0;i < n; ++i){
        for(int j = 0;j < n; ++j){
            if(i == j)continue;
            if(p[i][j] != p[j][i])return 0;
        }
    }
    for(int i = 0;i < n; ++i){
        vis[i] = false;
        for(int j = 0;j < n; ++j){
            if(p[i][j] == 2 && i != j){
                adj[i].pb(j);
            }
            if(p[i][j] == 1 && i != j){
                adj2[i].pb(j);
            }
        }
    }
 
    for(int i = 0;i < n; ++i){
        if(!vis[i]){
            component.clear();
            dfs(i);

            if(sz(component) == 2)return 0;
            for(int i = 0;i < sz(component); ++i){
                if(sz(component) > 1)ans[component[i]][component[(i + 1) % sz(component)]] = ans[component[(i + 1) % sz(component)]][component[i]] = 1;
                fuck.uni(component[i], component[(i + 1) % sz(component)]);
            }
 
            int prev = -1;
            for(int u: component){
                for(int v: adj2[u]){
                    if(!d.same_set(u, v)){
                        ans[u][v] = ans[v][u] = 1;
                        d.uni(u, v);
                    }
                }
 
                prev = u;
            }
        }
    }

    for(int i = 0;i < n; ++i){
        for(int j = 0;j < n; ++j){
            if(i == j)continue;
            if(ans[i][j] && !p[i][j])return 0;
            if(fuck.same_set(i, j) && !p[i][j])return 0;
            if(d.same_set(i, j) && !p[i][j])return 0;
        }
    }
    for(int i = 0;i < n; ++i){
        adj[i].clear();
        adj2[i].clear();
        vis[i] = false;
    }
    build(ans);
    return 1;
} 

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:89:17: warning: variable 'prev' set but not used [-Wunused-but-set-variable]
   89 |             int prev = -1;
      |                 ^~~~

• Subtask 1: 11 / 11
• Subtask 2: 10 / 10
• Subtask 3: 19 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4