제출 #860321

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
860321		anton	One-Way Streets (CEOI17_oneway)	C++17	100 / 100	205 ms	52052 KiB

oneway

#include<bits/stdc++.h>

using namespace std;
#define int long long
#define pii pair<int, int>

int n, m, p;
const int MAX_M = 1e5;
const int MAX_N = 1e5;

char status[MAX_M];

struct Node{
    vector<int> adj;
    vector<int> id;
    vector<int> dir;
    bool vis =false;
    int depth = 0;

    int open = 0;
} g[MAX_N], g2[MAX_N];


int dsu[MAX_N];
int sz[MAX_N];

int get(int id){
    vector<int> path;
    while(dsu[id]!=id){
        path.push_back(id);
        id = dsu[id];
    }
    for(auto e: path){
        dsu[e] = id;
    }
    return id;
}

void merge(int a, int b){

    ////cout<<a<<" and "<<b<<endl;
    a = get(a);
    b=  get(b);


    if(sz[a]<sz[b]){
        dsu[a] = b;
        sz[b] += sz[a];
    }
    else{
        dsu[b] = a;
        sz[a] += sz[b];
    }
}

int dfs(int u, int depth, int anc){
    //////cout<<"dfs "<<u<<" "<<depth<<endl;
    g[u].vis = true;
    g[u].depth = depth;
    int r = depth;
    for(int i= 0; i<g[u].adj.size(); i++){
        int v = g[u].adj[i];
        if(g[u].id[i] != anc){
            if(!g[v].vis){
                int val =dfs(v, depth+1, g[u].id[i]);
                if(val<=depth){
                    merge(u, v);
                }
                r = min(r, val);
            }
            else{
                int val = g[v].depth;
                if(val<=depth){
                    merge(u, v);
                }
                r = min(r, val);
            }
        }
    }

    return r;
}

pii edges[MAX_M];

const int MAX_P = 1e5;
pii pairs[MAX_P];

int dfs2(int id, int anc){
    g2[id].vis = true;
    int s= 0;
    for(int i = 0; i<g2[id].adj.size(); i++){
        if(g2[id].id[i] != anc){
            int c_s = dfs2(g2[id].adj[i], g2[id].id[i]);

            //cout<<g2[id].id[i]<<" "<<g2[id].dir[i]<<" "<<c_s<<endl;
            if(c_s ==0){
                status[g2[id].id[i]] = 'B';
            }
            else if(c_s >0){
                if(g2[id].dir[i] == -1){
                    status[g2[id].id[i]] = 'R';
                }  
                else{
                    status[g2[id].id[i]] = 'L';
                }
            }
            else{
                if(g2[id].dir[i] == -1){
                    status[g2[id].id[i]] = 'L';
                }
                else{
                    status[g2[id].id[i]] = 'R';
                }
            }
            s+=c_s;
        }
    }
    s+= g2[id].open;
    //cout<<id<<" "<<s<<endl;
    return s;
}

signed main(){
    cin>>n>>m;

    for(int i = 0; i<n; i++){
        dsu[i] = i;
        sz[i]=1;
    }
    for(int i = 0; i<m; i++){
        int a, b;
        cin>>a>>b;
        a--;b--;
        g[a].adj.push_back(b);
        g[b].adj.push_back(a);

        g[a].id.push_back(i);
        g[b].id.push_back(i);

        g[a].dir.push_back(1);
        g[b].dir.push_back(-1);

        edges[i].first = a;
        edges[i].second = b;
    }

    for(int i = 0; i<n; i++){

        if(!g[i].vis){
            dfs(i, 0, -1);
        }
    }

    ////cout<<"dfs done"<<endl;

    for(int i = 0; i<n; i++){
        //cout<<get(i)<<endl;
    }

    for(int i = 0; i<m; i++){
        if(get(edges[i].first) ==get(edges[i].second)){
            status[i] = 'B';
            ////cout<<i<<" ok"<<endl;
        }
        else{
            int a = get(edges[i].first);
            int b=  get(edges[i].second);
            g2[a].adj.push_back(b);
            g2[b].adj.push_back(a);
            g2[a].id.push_back(i);
            g2[b].id.push_back(i);
            g2[a].dir.push_back(1);
            g2[b].dir.push_back(-1);
        }
    }

    cin>>p;

    for(int i = 0; i<p; i++){
        cin>>pairs[i].first>>pairs[i].second;

        pairs[i].first--;pairs[i].second--;
        g2[get(pairs[i].first)].open ++;
        g2[get(pairs[i].second)].open--;
    }
    for(int i = 0; i<n; i++){
        if(!g2[get(i)].vis){
            dfs2(get(i), -1);
        }
    }

    for(int i = 0; i<m; i++){
        cout<<status[i];
    }
    cout<<endl;
}

컴파일 시 표준 에러 (stderr) 메시지

oneway.cpp: In function 'long long int dfs(long long int, long long int, long long int)':
oneway.cpp:61:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for(int i= 0; i<g[u].adj.size(); i++){
      |                   ~^~~~~~~~~~~~~~~~
oneway.cpp: In function 'long long int dfs2(long long int, long long int)':
oneway.cpp:92:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |     for(int i = 0; i<g2[id].adj.size(); i++){
      |                    ~^~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40