oj.uz

Submission #908073

# Submission time Handle Problem Language Result Execution time Memory
908073 2024-01-16T07:43:20 Z JakobZorz Parachute rings (IOI12_rings) C++17
37 / 100
 1284 ms 135084 KB 
#include<iostream>
#include<vector>
#include<unordered_set>
using namespace std;

int n;
vector<int>nodes[(int)1e6];
unordered_set<int>num3;
int num4=-1;
int num3n[(int)1e6];
int num_cycles;
unordered_set<int>cycle;

int dsu_parent[(int)1e6];
int dsu_get(int a){
    if(dsu_parent[a]<0)
        return a;
    return dsu_parent[a]=dsu_get(dsu_parent[a]);
}

void dsu_merge(int a,int b){
    a=dsu_get(a);
    b=dsu_get(b);
    if(a==b)
        return;
    if(dsu_parent[a]>dsu_parent[b])
        swap(a,b);
    dsu_parent[a]+=dsu_parent[b];
    dsu_parent[b]=a;
}

void Init(int N){
    n=N;
    for(int i=0;i<1e6;i++)
        dsu_parent[i]=-1;
}

int cvis;
int vis[(int)1e6];
int dfs(int node,int d,int end){ // -1 = dead end
    int pv=vis[node];
    vis[node]=cvis;
    
    for(int ne:nodes[node]){
        if(ne==end&&d>1)
            return end;
        if(vis[ne]!=cvis&&vis[ne]!=0)
            return ne;
            
        if(vis[ne]==0){
            int r=dfs(ne,d+1,end);
            if(r!=-1)
                return r;
        }
    }
    
    vis[node]=pv;
    return -1;
}

void conn(int a,int b){
    nodes[a].push_back(b);
    if(nodes[a].size()==3){
        num3.insert(a);
        for(int ne:nodes[a])
            num3n[ne]++;
    }
    
    if(nodes[a].size()==4){
        num3.erase(a);
        if(num4==-1)
            num4=a;
        else
            num4=-2;
        for(int ne:nodes[a])
            num3n[ne]--;
    }
}

void Link(int a,int b){
    conn(a,b);
    conn(b,a);
    
    if(dsu_get(a)==dsu_get(b)){
        if(num_cycles==0){
            cvis++;
            dfs(a,0,a);
            for(int i=0;i<1e6;i++)
                if(vis[i]==cvis){
                    cycle.insert(i);
                }
            num_cycles=1;
        }else if(num_cycles==1){
            if(vis[a])
                swap(a,b);
            if(vis[a]){
                if(vis[a]!=vis[b]){
                    num_cycles=2;
                    return;
                }
                
                if(cycle.count(a)&&cycle.count(b)){
                    cycle={a,b};
                }else{
                    num_cycles=2;
                }
                return;
            }
            
            unordered_set<int>s;
            int cnt=0;
            for(int ne:nodes[a]){
                cvis++;
                vis[a]=cvis;
                int r=dfs(ne,1,a);
                if(r!=-1){
                    s.insert(r);
                    cnt++;
                }
            }
            
            //cout<<"CNT: "<<cnt<<"\n";
            if(s.size()!=1||cnt!=2){
                num_cycles=2;
            }else{
                int center=*s.begin();
                if(cycle.find(center)!=cycle.end()){
                    cycle={center};
                    //cout<<"CYCLE: "<<center<<"\n";
                }else
                    num_cycles=2;
            }
        }else{
            num_cycles=2;
        }
    }else{
        dsu_merge(a,b);
    }
}

bool check(int i){
    bool in_cycle=true;
    if(num_cycles==1)
        in_cycle=cycle.find(i)!=cycle.end();
    /*cout<<"checking "<<i<<"\n";
    cout<<(num3n[i]==(int)num3.size())<<" ";
    cout<<(nodes[i].size()==3&&num3n[i]==(int)num3.size()-1)<<" ";
    cout<<in_cycle<<"\n";*/
    return (num3n[i]==(int)num3.size()||(nodes[i].size()==3&&num3n[i]==(int)num3.size()-1))&&in_cycle;
}

int CountCritical(){
    if(num_cycles>=2)
        return 0;
    if(num3.size()>4)
        return 0;
    if(num4==-2)
        return 0;
    if(num4!=-1){
        bool in_cycle=true;
        if(num_cycles==1)
            in_cycle=cycle.find(num4)!=cycle.end();
        return num3n[num4]==num3.size()&&in_cycle;
    }
    
    if(num3.empty()&&num_cycles==1)
        return cycle.size();
    
    if(num3.empty())
        return n;
    
    int res=0;
    unordered_set<int>s;
    for(int i:num3){
        for(int ne:nodes[i]){
            if(check(ne))
                s.insert(ne);
        }
        if(check(i))
            s.insert(i);
    }
    return (int)s.size();
}

Compilation message

rings.cpp: In function 'int CountCritical()':
rings.cpp:163:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::unordered_set<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  163 |         return num3n[num4]==num3.size()&&in_cycle;
      |                ~~~~~~~~~~~^~~~~~~~~~~~~
rings.cpp:172:9: warning: unused variable 'res' [-Wunused-variable]
  172 |     int res=0;
      |         ^~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 31324 KB Output is correct
2 Correct 11 ms 31580 KB Output is correct
3 Correct 11 ms 31432 KB Output is correct
4 Correct 12 ms 31320 KB Output is correct
5 Correct 12 ms 31576 KB Output is correct
6 Correct 12 ms 31836 KB Output is correct
7 Correct 10 ms 31436 KB Output is correct
8 Correct 11 ms 31576 KB Output is correct
9 Correct 11 ms 31580 KB Output is correct
10 Correct 12 ms 31576 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 291 ms 54584 KB Output is correct
2 Correct 743 ms 68960 KB Output is correct
3 Correct 1284 ms 81944 KB Output is correct
4 Correct 916 ms 76596 KB Output is correct
5 Correct 953 ms 80144 KB Output is correct
6 Correct 1210 ms 135084 KB Output is correct
7 Correct 1130 ms 80548 KB Output is correct
8 Correct 852 ms 75220 KB Output is correct
9 Correct 893 ms 77716 KB Output is correct
10 Correct 536 ms 75876 KB Output is correct

Subtask #3
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 31324 KB Output is correct
2 Correct 11 ms 31580 KB Output is correct
3 Correct 11 ms 31432 KB Output is correct
4 Correct 12 ms 31320 KB Output is correct
5 Correct 12 ms 31576 KB Output is correct
6 Correct 12 ms 31836 KB Output is correct
7 Correct 10 ms 31436 KB Output is correct
8 Correct 11 ms 31576 KB Output is correct
9 Correct 11 ms 31580 KB Output is correct
10 Correct 12 ms 31576 KB Output is correct
11 Correct 12 ms 31576 KB Output is correct
12 Correct 13 ms 31936 KB Output is correct
13 Correct 13 ms 31836 KB Output is correct
14 Incorrect 13 ms 31580 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #4
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 31324 KB Output is correct
2 Correct 11 ms 31580 KB Output is correct
3 Correct 11 ms 31432 KB Output is correct
4 Correct 12 ms 31320 KB Output is correct
5 Correct 12 ms 31576 KB Output is correct
6 Correct 12 ms 31836 KB Output is correct
7 Correct 10 ms 31436 KB Output is correct
8 Correct 11 ms 31576 KB Output is correct
9 Correct 11 ms 31580 KB Output is correct
10 Correct 12 ms 31576 KB Output is correct
11 Correct 12 ms 31576 KB Output is correct
12 Correct 13 ms 31936 KB Output is correct
13 Correct 13 ms 31836 KB Output is correct
14 Incorrect 13 ms 31580 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #5
0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 31324 KB Output is correct
2 Correct 11 ms 31580 KB Output is correct
3 Correct 11 ms 31432 KB Output is correct
4 Correct 12 ms 31320 KB Output is correct
5 Correct 12 ms 31576 KB Output is correct
6 Correct 12 ms 31836 KB Output is correct
7 Correct 10 ms 31436 KB Output is correct
8 Correct 11 ms 31576 KB Output is correct
9 Correct 11 ms 31580 KB Output is correct
10 Correct 12 ms 31576 KB Output is correct
11 Correct 291 ms 54584 KB Output is correct
12 Correct 743 ms 68960 KB Output is correct
13 Correct 1284 ms 81944 KB Output is correct
14 Correct 916 ms 76596 KB Output is correct
15 Correct 953 ms 80144 KB Output is correct
16 Correct 1210 ms 135084 KB Output is correct
17 Correct 1130 ms 80548 KB Output is correct
18 Correct 852 ms 75220 KB Output is correct
19 Correct 893 ms 77716 KB Output is correct
20 Correct 536 ms 75876 KB Output is correct
21 Correct 12 ms 31576 KB Output is correct
22 Correct 13 ms 31936 KB Output is correct
23 Correct 13 ms 31836 KB Output is correct
24 Incorrect 13 ms 31580 KB Output isn't correct
25 Halted 0 ms 0 KB -