Submission #828166

#	Time	Username	Problem	Language	Result	Execution time	Memory
828166		jlallas384	Parachute rings (IOI12_rings)	C++17	20 / 100	4086 ms	152796 KiB

rings

#include <bits/stdc++.h>
using namespace std;
 
 
 
struct ufds{
    vector<int> sz, par;
    ufds(){}
    ufds(int n): sz(n, 1), par(n){
        iota(par.begin(), par.end(), 0);
    }
    int find(int a){
        return par[a] == a ? a : par[a] = find(par[a]);
    }
    int unite(int a, int b){
        a = find(a), b = find(b);
        if(a == b) return 0;
        if(sz[a] < sz[b]) swap(a, b);
        par[b] = a;
        sz[a] += sz[b];
        return 1;
    }
};
 
set<int> ans;
vector<vector<int>> g, tree;
vector<int> deg;
int n;
ufds ds;
 
int bad = 0;
int d4 = 0;
 
void Init(int N){
    n = N;
    g.resize(n);
    tree.resize(n);
    deg.resize(n);
    for(int i = 0; i < n; i++){
        ans.insert(i);
    }
    ds = ufds(n);
}
 
void proc(int a, int add = 1){
    if(deg[a] == 4){
        if(add){
            d4++;
            if(d4 == 2) bad = 1;
        }
        if(!ans.count(a)) ans = {};
        else ans = {a};
    }else if(deg[a] == 3){
        set<int> nans;
        if(ans.count(a)) nans.insert(a);
        for(int u: g[a]){
            if(ans.count(u)) nans.insert(u);
        }
        ans = nans;
    }
}
 

 
 
 
 
int cyc = 0;
 
vector<int> path;
int dfs(int v, int p, int x){
    path.push_back(v);
    if(v == x) return 1;
    for(int u: tree[v]) if(u != p){
        if(dfs(u, v, x)) return 1;
    }
    path.pop_back();
    return 0;
}

vector<pair<int,int>> eds;


void Link(int a, int b){
    int res = ds.unite(a, b);
    deg[a]++, deg[b]++;
    g[a].push_back(b);
    g[b].push_back(a);
    eds.emplace_back(a, b);
    proc(a), proc(b);
    cyc += !res;
}

int CountCritical(){    
    if(cyc == 0) return ans.size();
    int fans = 0;
    for(int x: ans){
        ufds f(n);
        int can = 1;
        for(auto [u, v]: eds) if(u != x && v != x){
            if(!f.unite(u, v)) can = 0;
        }
        fans += can;
    }
    return fans;
}

• Subtask 1: 20 / 20
• Subtask 2: 0 / 17
• Subtask 3: 0 / 18
• Subtask 4: 0 / 14
• Subtask 5: 0 / 31