Submission #1049480

#	Time	Username	Problem	Language	Result	Execution time	Memory
1049480		Ludissey	Graph (BOI20_graph)	C++17	58 / 100	389 ms	35940 KiB

Graph

#include <bits/stdc++.h>
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
 
using namespace std;
 
vector<vector<int>> neigh1;
vector<vector<int>> neigh2;
vector<int> sz;
vector<int> visited;
vector<int> parent;
vector<int> eqCOLOR;
 
bool no=false;
 
int getParent(int a){
    return (a==parent[a]) ? a : parent[a]=getParent(parent[a]); 
}
 
void unite(int a, int b){
    a=getParent(a); b=getParent(b);
    if(a==b) return;
    if(sz[a]<sz[b]) swap(a,b);
    sz[a]+=sz[b];
    parent[b]=a;
}
 
vector<vector<pair<int,int>>> neigh;
 
void dfs(int x, int c){
    eqCOLOR[x]=c;
    visited[x]=true;
    for (auto u : neigh[x])
    {
        if(eqCOLOR[u.first]!=-1&&eqCOLOR[u.first]!=(u.second*2)-c) no=true;
        if(visited[u.first]) continue;
        dfs(u.first,(u.second*2)-c);
    }
}
 
int colorCOUNT(int x){
    int sm=abs(eqCOLOR[x])*sz[x];
    visited[x]=false;
    eqCOLOR[x]=-1;
    for (auto u : neigh[x])
    {
        if(!visited[u.first]) continue;
        sm+=colorCOUNT(u.first);
    }
    return sm;
}
 
signed main() {
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    int N,M; cin >> N >> M;
    neigh1.resize(N);
    sz.resize(N,1);
    parent.resize(N,1);
    eqCOLOR.resize(N,-1);
    neigh2.resize(N);
    vector<pair<pair<int,int>,int>> ed(M);
    for (int i = 0; i < N; i++) parent[i]=i;
    
    for (int i = 0; i < M; i++)
    {
        int a,b,c; cin >> a >> b >> c;
        a--;
        b--;
        if(c==1){
            neigh1[a].push_back(b);
            neigh1[b].push_back(a);
        }else{
            neigh2[a].push_back(b);
            neigh2[b].push_back(a);
        }
        ed[i]={{a,b},c};
    }
    for (int i = 0; i < N; i++){
        for (int j = 1; j < sz(neigh1[i]); j++)  unite(neigh1[i][j-1],neigh1[i][j]);
        for (int j = 1; j < sz(neigh2[i]); j++)  unite(neigh2[i][j-1],neigh2[i][j]);
    }
    unordered_map<int,int> mp;
    for (int i = 0; i < N; i++){
        for (int j = 0; j < sz(neigh1[i]); j++) mp[getParent(neigh1[i][j])]=i+1;
        for (int j = 0; j < sz(neigh2[i]); j++) {
            if(mp[getParent(neigh2[i][j])]==i+1) {
                cout << "NO\n";
                return 0;
            }
        }
    }
    for (int i = 0; i < N; i++){
        for (int j = 0; j < sz(neigh1[i]); j++) {
            if(getParent(i)==getParent(neigh1[i][j])) {
                if(eqCOLOR[getParent(i)]==2){
                    cout << "NO\n";
                    return 0;
                } 
                eqCOLOR[getParent(i)]=1;
            }
        }
        for (int j = 0; j < sz(neigh2[i]); j++) {
            if(getParent(i)==getParent(neigh2[i][j])) {
                if(eqCOLOR[getParent(i)]==1) {
                    cout << "NO\n";
                    return 0;
                }
                eqCOLOR[getParent(i)]=2;
            }
        }
    }
    vector<set<pair<int,int>>> neighCOPY(N);
    neigh.resize(N);
    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < sz(neigh1[i]); j++) {
            if(getParent(i)!=getParent(neigh1[i][j])) neighCOPY[getParent(i)].insert({getParent(neigh1[i][j]),1});
        }  
        for (int j = 0; j < sz(neigh2[i]); j++) {
            if(getParent(i)!=getParent(neigh2[i][j])) neighCOPY[getParent(i)].insert({getParent(neigh2[i][j]),2});
        }
    }
    for (int i = 0; i < N; i++)
    {
        for (auto u : neighCOPY[i])
        {
            neigh[i].push_back(u);
        }
        
    }
    
    visited.resize(N,false);
    unordered_set<int> st;
    for (int i = 0; i < N; i++) st.insert(getParent(i));
    for (auto j : st){
        if(!visited[j]&&eqCOLOR[j]>0) dfs(j,eqCOLOR[j]);
    }
    if(no) { cout << "NO\n"; return 0; }
     for (auto j : st){
        if(!visited[j]){
            if(sz(neigh[j])==0) dfs(j,0); // securite
            else{
                int mn=1e9,mnI=0;
                for (int k = -70; k <= 70; k++) // sinon binary 
                { 
                    dfs(j,k);
                    int c=colorCOUNT(j);
                    if(no) { no=false; continue; }
                    if(c<mn) { mn=c; mnI=k; } 
                }
                dfs(j,mnI);
            }
        }
    }
    for (int i = 0; i < M; i++)
    {
        if(eqCOLOR[getParent(ed[i].first.first)]+eqCOLOR[getParent(ed[i].first.second)]!=ed[i].second*2) no=true;
    }
    
    if(no){
        cout << "NO\n";
    }else{
        cout << "YES\n";
        for (int i = 0; i < N; i++)
        {
            cout << (double)(eqCOLOR[getParent(i)])/2<<" ";
        }
        
    }
    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 12 / 12
• Subtask 3: 17 / 17
• Subtask 4: 24 / 24
• Subtask 5: 0 / 42