Submission #343337

#	Time	Username	Problem	Language	Result	Execution time	Memory
343337		benedict0724	One-Way Streets (CEOI17_oneway)	C++17	30 / 100	11 ms	640 KiB

oneway

#include <bits/stdc++.h>

using namespace std;

vector<int> adj[1002];
pair<int, int> road[1002];
pair<int, int> haveTo[1002];
int subOf[1002];
bool visited[1002];
bool poss = false;

void dfs(int x, int s, int e){
    visited[x] = true;
    if(x == e){
        poss = true;
        return;
    }
    subOf[x] = 1;
    for(auto u : adj[x]){
        if(!visited[u] && (x != s || u != e)){
            dfs(u, s, e);
        }
        if(poss) return;
    }
}

int main()
{
    int n, m;
    scanf("%d %d", &n, &m);
    for(int i=1;i<=m;i++){
        int s, e;
        scanf("%d %d", &s, &e);
        adj[s].push_back(e);
        adj[e].push_back(s);
        road[i] = {s, e};
    }
    int p;
    scanf("%d", &p);
    for(int i=1;i<=p;i++){
        int s, e;
        scanf("%d %d", &s, &e);
        haveTo[i] = {s, e};
    }

    for(int i=1;i<=m;i++){
        int s = road[i].first, e = road[i].second;
        bool toL = true, toR = true;
        fill(visited, visited + 1002, false);
        fill(subOf, subOf + 1002, 0);
        poss = false;
        int cnt = 0;
        for(auto u : adj[s]){
            if(u == e) cnt++;
        }
        if(cnt > 1){
            printf("B");
            continue;
        }
        dfs(s, s, e);
        if(poss){
            printf("B");
        }
        else{
            for(int j=1;j<=p;j++){
                if(subOf[haveTo[j].first] == 1 && subOf[haveTo[j].second] == 0){
                    toL = false;
                }
                if(subOf[haveTo[j].first] == 0 && subOf[haveTo[j].second] == 1){
                    toR = false;
                }
            }
            if(toL && toR) printf("B");
            else if(toL) printf("L");
            else printf("R");
        }
    }
}

Compilation message (stderr)

oneway.cpp: In function 'int main()':
oneway.cpp:30:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   30 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
oneway.cpp:33:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   33 |         scanf("%d %d", &s, &e);
      |         ~~~~~^~~~~~~~~~~~~~~~~
oneway.cpp:39:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   39 |     scanf("%d", &p);
      |     ~~~~~^~~~~~~~~~
oneway.cpp:42:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   42 |         scanf("%d %d", &s, &e);
      |         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40