Submission #43412

#	Time	Username	Problem	Language	Result	Execution time	Memory
43412		Hassoony	007 (CEOI14_007)	C++14	0 / 100	376 ms	17308 KiB

007

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
const int MX=2e5+9;
int n,m,a,b,s,d,dis[MX],dis1[MX],x,y,vis[MX];
vector<int>v[MX];
void bfs(int x,int y){
    for(int i=1;i<=n;i++)dis[i]=MX,vis[i]=0;
    dis[x]=0;
    queue<int>q;
    q.push(x);
    while(!q.empty()){
        int node=q.front();q.pop();
        if(vis[node])continue;
        vis[node]=1;
        for(auto pp:v[node]){
            if(pp==y)continue;
            if(dis[pp]==MX){
                dis[pp]=dis[node]+1;
                q.push(pp);
            }
        }
    }
}
int main(){
    scanf("%d%d",&n,&m);
    scanf("%d%d%d%d",&s,&d,&a,&b);
    for(int i=0;i<m;i++){
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    bfs(s,d);
    for(int i=1;i<=n;i++)dis1[i]=dis[i];
    bfs(d,s);
    if(dis[a]<dis1[a]||dis[b]<dis1[b]){
        puts("-1");
        return 0;
    }
    bfs(s,0);
    for(int i=1;i<=n;i++)dis1[i]=dis[i];
    bfs(d,0);
    if(dis[a]<dis[b]){
        cout<<dis[a]-dis1[a]<<endl;
    }
    else cout<<dis[b]-dis1[b]<<endl;
}

Compilation message (stderr)

007.cpp: In function 'int main()':
007.cpp:27:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
                        ^
007.cpp:28:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d%d",&s,&d,&a,&b);
                                  ^
007.cpp:30:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&x,&y);
                            ^

• Subtask 1: 0 / 30
• Subtask 2: 0 / 70