Submission #796698

#	Time	Username	Problem	Language	Result	Execution time	Memory
796698		jlallas384	Parachute rings (IOI12_rings)	C++17	55 / 100	4048 ms	98692 KiB

rings

    #include <bits/stdc++.h>
    using namespace std;
     
    vector<vector<int>> g;
    int n;
    vector<int> deg;
     
    void Init(int N){
        n = N;
        g.resize(n);
        deg.assign(n, 0);
    }
     
    vector<int> cc, vis;
    int cyc = 0;
    void dfs(int v, int p, int gg = 1){
        vis[v] = 1;
        if(gg) cc.push_back(v);
        for(int u: g[v]){
            if(!vis[u]) dfs(u, v, gg);
            else if(vis[u] == 1 && u != p){
            	cyc = 1;
            }
        }
    }
     
    int CountCritical(){    
        vis.assign(n, 0);
        int ans = 0;
        int cnt = 0;
        int has = 0;
        int d4 = 0;
        for(int i = 0; i < n; i++){
            cnt += deg[i] >= 3;
            if(d4 && deg[i] > 3) return 0;
            d4 |= deg[i] > 3;
        }
        for(int i = 0; i < n; i++) if(!vis[i]){
            cc.clear();
            cyc = 0;
            dfs(i, -1);
            int t3 = 0;
            for(int v: cc){
                if(deg[v] >= 3) t3 = 1;
            }
            if(t3 || cyc){
                if(has) return 0;
                has = 1;
                ans = 0;
                int mx = 0;
                for(int v: cc){
                    mx = max(mx, deg[v]);
                }
                if(mx == 2) ans += cc.size();
                else{
                    int nw = 0;
                    set<int> st;
                    for(int v: cc){
                    	st.insert(v);
                    }
                    for(int v: cc) if(deg[v] == mx){
                    	set<int> stn;
                    	if(st.count(v)) stn.insert(v);
                    	for(int u: g[v]){
                    		if(st.count(u)) stn.insert(u);
                    	}
                    	st = stn;
                    }
                    for(int v: st) if(deg[v] == mx || mx == 3){
                        for(int x: cc){
                            vis[x] = 0;
                        }
                        vis[v] = 2;
                        cyc = 0;
                        for(int x: cc) if(!vis[x]){
                            dfs(x, -1, 0);
                        }
                        if(cyc == 0){
                            int t = cnt - (deg[v] >= 3); 
                            for(int u: g[v]){
                                t -= (deg[u] == 3);
                            }
                            nw += (t == 0);
                        }
                    }
                    if(nw == 0) return 0;
                    else ans += nw;
                }
            }else{
                if(!has){
                    int nw = 0;
                    int hv = 0;
                    for(int v: cc){
                        int t = cnt - (deg[v] >= 3); 
                        hv |= deg[i] >= 3;
                        for(int u: g[v]){
                            t -= (deg[u] == 3);
                        }
                        nw += (t == 0);
                    }
                    if(hv && nw == 0) return 0;
                    else{
                        ans += nw;
                    }
                }
            }
        }
        return ans;
    }
     
    void Link(int a, int b){
        g[a].push_back(b);
        g[b].push_back(a);
        deg[a]++;
        deg[b]++;
    }

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